> I can take cash from any country in the world to my local bank, and deposit it into my account.

If you are at a institution bank, probably but that's a non-existent use case - I never had Argentinian Pesos, Turkish Lira or Bulgarian Lev I suddenly needed to deposit into my bank account !..

> Try to use cryptocurrency for anything other than a few very specific transactions at a number of places in the world so small that it's a rounding error.

I'm not sure whether you travel much, but I always travel as a digital nomad. I pay small transactions with local cash or mostly bank cards as everybody does. But big amounts? That's where crypto comes into play. I've paid in crypto transactions worth a few thousands dollars because that's the only way to do it without incurring huge transaction fees and / or long processing time.