I don’t understand the benefit of changing money in the app when the card automatically changes money at the best rate when you purchase. Anyone know?
Some merchants/ATMs could apply a markup when exchanging and you avoid that (and get the best rate!) by exchanging it beforehand in-app
Securing your preferred exchange rate if a particular currency is volatile.
e.g. Pound sterling during the aftermath of Brexit.
If you want to transfer currency to another country / currency (not a card payment)
I.E, I transfer in to Revolut in Sterling, convert to €, then transfer out to my eurozone account.