That argument doesn't make much sense. You don't control your bank balance, which are just IOUs, either. It's just an entry in some centralized company's database.
If a video game company decides my points are now worth half as much, or that they’ve expired, that’s their prerogative — and if I don’t like it that’s too bad. If a bank tried to do that, they’d get hit with a ton of lawsuits that they’d definitely lose.
The point I'm trying to make is that it's not fundamentally as different from an in-game currency as you think it is. The cycles just happen much less frequently over longer periods of time (companies go bankrupt and change faster than wars happens) so you may never see it in your lifetime if you're lucky.
[0] https://www.timesofisrael.com/lebanese-cafe-owner-hailed-for...