I would happily use Tether, Shib, beanie babies, USD as medium of exchange if I trusted that the exchange took place in a timeline I wanted. I'm not comfortable holding tether for more than a few minutes, and I'm not comfortable holding USD for more than a few years.

The problem is getting stuck holding the asset for a long period of time. USD will lose 80% of it's value over the next 50 years. Tether likely will lose 100% in that time frame.