Bitcoin inflation rate per annum: 3.87%
USD Current inflation rate for the United States is Early in Bitcoin history, by design Bitcoin went though a period of hyperinflation where Satoshi and a few users acquired most of the coins in circulation.
Aprox 4.11% of Bitcoin users (addresses) control 96.53% of all bitcoins in circulation.
Also there's a chance that something will make Bitcoin obsolete in the near future - immediately destroying the trade value of Bitcoin, either a new cryptocurrency, a quantum computer or cryptographic breakthrough that would allow theft of BTC private keys or more predictably a bug like what recently happened in the main Bitcoin core wallet client software which allowed a user to inflate the supply of Bitcoins past 21 million and mint more BTC for free.
So if you were truly concerned about long term stability - gold or tangible functional assets would be much safer than software based pet rocks.
https://www.livebitcoinnews.com/cve-2018-17144-the-aftermath...
The obvious worst part of this bug was the inflation
exploit. An attack could create new bitcoins at will,
exceeding the 21 million hard cap limit that is
currently in place. This would absolutely destroy
confidence in not only Bitcoin, but every
cryptocurrency.
In addition, a miner could crash every single node they
are connected to by producing a block with an invalid
transaction in it. Miners are will go out of their way
to connect to as many other mining nodes as possible, so
they receive notifications of blocks faster.
Imagine you’re a miner, hashing away at block #1000.
Another miner, Jim, finds block #1001 and starts
propagating it around the network. However, you’re not
connected to Jim, so it takes an extra few seconds for
you to receive the block. During those few seconds, the
network has moved on and you’re wasting hashpower and in
turn money. You need to receive the new block before you
get started on the next one.
All the miners are highly connected, so if one is
producing client-crashing blocks, many of the larger
miners would be hit.
However, it is more common to measure inflation by the increase in nominal prices of goods, as I did above with gold. And, by this measure, Bitcoin is deflating. It's hard to measure the deflation rate with precision because it's so volatile, but at the beginning of 2011, it was worth 10¢, and now it's US$6600. It's oscillated wildly around the exponential trend line by about a factor of 3 on each side, but the trend line itself is a deflation by about 75% per year (or of 300% per year, if you look at deflation that way.)
Presumably this won't continue forever, as it's more appropriate to tulip bulbs than to a usable currency, but it is certainly quite far from inflation in the usual sense.
The vast majority of the supply is owned by a very small oligarch.
The chances of Bitcoin becoming obsolete or failing catastrphically due to a glitch or bug in the protocol software - like what just happened a few days ago (luckily by someone who desired to fix it, if the bug was found by a malicious actor they would have destroyed the entire Bitcoin ecosystem), the cryptocoin software can not be guaranteed as a safe store of value.
Anyone who "invested" in Bitcoin at the start of this year has lost upwards of 50%, so that would qualify as inflation in your terms. Other cryptocoins have seen losses exceeding 80%-90%.
The way cryptocoins work is by early users dumping their supply onto new users to exit and extract real value from the suckers who then become bag holders, the new users hope to do the same but are at a severe disadvantage to early users who own the vast majority of the supply.
What people actually mean when they say "not controlled by a government" is that the dollar has lost 98.3% of its value since its peak in 1792–1833. It fell 6.3% in 1834, but stayed at that value (with occasional deviations downwards) until 1932. From 1932 to 1970, it lost 47% of its value, mostly in 1933. In 1971, it became a fiat currency, and fiat currencies are famously prone to inflation; since 1970, the dollar has lost 96.6% of its remaining value.
I'm measuring the dollar against gold here, not just because gold was what defined its value from 1792 to 1970 (and part of 1971), but because gold was the standard of value for international commerce from sometime around 100 BCE until 1971. You could reasonably use a different good as the standard of value, and you'll probably get marginally different results, although a few goods (passenger pigeons, 32-bit multiplications, warships) will give you significantly different results. Gold is relatively convenient for this because of the wide availability and verifiability of its price. Gold's short-term volatility makes it useless for very short-term comparisons, though, by which I mean anything less than 10 years.
When Bitcoin people say they want a "currency not controlled by a government", they mean that they don't want 97% of their savings to evaporate in a mere 50 years because the government decided that printing money was a good way to meet its payroll and pay its bonds.
As fiat currencies go, dollars are actually doing pretty well. Here in Argentina, our peso has lost about 25% of its value each year for the last several years, but this year, it's accelerated; it's lost 50% of its value since April. (It's worth 5¢ today, down from 10¢ in April.) And of course everyone remembers Zimbabwe's hundred-trillion-dollar bills.
Now, you could argue that 5% inflation per year doesn't really impair a currency's use as a measure of value or a medium of exchange, only as a store of value. And you might be right. But there are a bunch of people out there who would love to have a secure store of value that they can also spend, which is why the dollar price of gold more than tripled in 2005–2012. (It's recovered a bit since then.)
I am not going to take a position here on whether providing a potentially safer store of value than dollars is a good thing or a bad thing. It's a thing some people want, and you might not want them to have it. That's okay. I'm just pointing out that they want it, and it's not the same thing as money laundering.
(Historical gold price data from http://onlygold.com/m/Prices/Prices200Years.asp.)