QED
If you're going to let the future determine your transaction patterns too much you will quite literally starve in the present. So even in that scenario there will be transactions and people will be happy to take your coin because they too hope that its value will go up. Obviously once a large fraction of world trade would be in a currency like that the currency itself would start to exhibit the same traits as the global economy and this effect would mostly cancel out any inherent properties.
Effectively: bitcoin was underpriced at the beginning to the point that it could only go up, the question is how far it will do that before it will have expanded to fill the niches where it fits. As soon as that has happened it will cease to increase.
That's the problem with this doublespeak, where people intentionally fool themselves into cognitive dissonance.
The whole point of currency is not investment. It's the exact opposite of investment. Currency is intended to have stable value over time, because it's whole point is to serve as a unit of account, store value, and serve as a medium to exchange value in an economy.
By it's very definition "investing" implies the expectation of profit. Think about it for a second: how can something intended to have a stable value be considered apt for speculation?
Point is that even with stable prices, there is plenty of room for speculators.
Even if you feel the need to equate crypto-things to bonds, first you need to argue why buying, say, bitcoins can be argued as lending money to someone, which makes no sense whatsoever.
Cryptos are nothing more than speculation vehicle, and it's pretty obvious that they are massively used as a pump-and-dump scheme. The only point in time where cryptos played a relevant role as a currency was way back in the silk road times where cryptos were used with the expectation of laundring transactions. That usecases quickly went out the door ages ago.
https://blockfi.com/an-introduction-to-rehypothecation-with-...
So some people of reinvented fractional reserve banking. But now with the problem that it’s unregulated, unbackstopped by a lender of last resort and ultimately through rehypothecation you’ve virtually eliminated any advantage gained by using blockchain technology.
I'm sure bitcoin purist will hate it, but afaik there's a lot of btc being held at exchanges (e.g. coinbase).
Technically instead of holding BTC there, you could be holding cBTC (value in a coinbase btc deposit account) and coinbase could issue cBTC loans similar to banks.
(The issue is that there's no backstop like in the real world, where central bank can step in as lender of last resort to avoid bank runs)
In the money as credit model, the money supply expands and subtracts with economic activity. And the best suited money have price stability so the market of credit can focus "pricing" risk correctly.
This model of money could be supported by some kind of cryptocurrency, however right now the investors don't seem to have an appetite for sponsoring that sort of thing.