And Bitcoin deflated by 18%

https://finance.yahoo.com/quote/BTC-USD/history/

43,565.51 on January 6, 2022

36,833.88 on January 6, 2021

Yes, but I think the more crucial aspect is not how much it's gone up or down in a given year, but more the secular trend. The dollar has a secular inflation trend, having lost something like 95% of its value over the last 50 years, because that's just what fiat currencies do, while Bitcoin was designed to not have the structural incentives that cause that. Indeed, some have argued that Bitcoin is inherently deflationary, which would make it an ideal savings vehicle if true.

How's Not Mimblewimble going?

The "ISO Standard" argument against inflation is that it favors the capital class over the middle and lower class, because money loses value over time faster than capital does. This means it steals from the poor and gives to the rich, because the upper class puts most of their wealth into capital, because they have a higher return on investment, while the poor and middle class store most of their wealth in savings accounts, because they need the ability to access significant chunks of their wealth in a hurry if they suffer an emergency (the rich have "lots" of cash on hand, too, but it is a smaller fraction of their overall wealth).

This seems like it implies that a deflationary currency would be better, but it does not, because in a deflationary economy, the behavior of the rich would change. In effect, the rich would keep most of their wealth in cash, while the middle class and the poor would not be able to change their behavior at all. The middle class family that has 50% of their wealth tied up in a house would still have that wealth tied up in a house because they actually need to live in it. A rich investor who owns hundreds of houses in the current economy would, however, move their wealth into cash and sell the houses. It might help the housing market, but it would screw up the currency market in exchange, and would probably not do anything for wealth disparity.

In short, "wealth" is the ability to make a wider range of choices. Both paths, deflation and inflation, favor the wealthy over the poor because of this.

However, the interests of a person trying to figure out how to save money run counter to saving it in an inflating instrument like the ARS, or, to a lesser extent, the dollar. From that perspective, deflation is even better than stability. Bitcoin is likely an improvement for the individual person who chooses it, independent of how it affects the economy for the wealthy to rebalance their portfolio away from REITs and toward Bitcoin, if that happens.

I agree that Bitcoin would be a lot more useful if its value were less unstable.

6% is fine, at least it's not +/-100% and it's accepted everywhere. For now.

It's fine as a medium of exchange or a unit of account; as a store of value, 6% inflation in a year is disastrous.

6% was just one year, not a long term value.

And nobody should be using common currency as a store of value.

The USD is designed to have a bit of inflation, i.e. it's not supposed to be a store of value on purpose.

It's true that we don't know whether US$ inflation this year will be 1% or 12%, but that's not actually better than a predictable 6% per year inflation rate. It's worse. A predictable inflation rate could be priced into things like bond yields.

Use as a store of value is a significant part of what we're talking about here. You said, "Argentinians who want to avoid their own currency would be 10x better served by USD than BTC." Why do you think Argentines want to avoid our own currency? Part of it is that it's useless for export; nobody abroad has AR$.

But the main reason is that designed-in secular inflation makes it a shitty store of value. This was specifically mentioned in the comment you were replying to: "Not only that, you also are forbid from buying dollars, so if you want to get them to avoid our rampant inflation (50% average, around 100% for groceries) you only have the black market which is around 200 pesos." Bitcoin has its own problems, like volatility, but it doesn't have that one.

Why would you claim that people wanting to "avoid rampant inflation" would be "10x better served by USD than BTC"? We can now discard the hypothesis that you don't know about the secular inflation of the US$, since you explained it yourself in your own words in the comment I am replying to. It seems like you were being, at best, careless with the truth.