For the common transactions people make, crypto is both slow and expensive. I can Zelle someone instantly, for free. In the EU, Australia, etc., bank-to-bank transfers are similarly instant. I don't know that Bitcoin etc. ever get to totally free in this fashion, and it's probably 99.9% of most people's money transfer usage.
For the uncommon transactions - like the $50k international transfer you mention - slow tends to be OK, and it's likely gonna have some expense either way.
Short version: In contrived scenarios, Bitcoin may come out on top, but that's not likely to convince many people.
All "common transactions" use credit (even when you use a debit card). The banks approve transactions quickly, but reconcile those transactions slowly.
It'll be the same for any crypto that takes off but needs to reconcile slowly.
In a crypto world, you don't need to convert to Euros. Are we in a crypto world yet? No. Will we live in crypto world in the future? Maybe, when it's faster and cheaper ;).