How can you be sure that the sats in your WoS or Alby wallet are real before you spend them? How can you be sure that you will be able to spend your BTC on a centralized exchange tomorrow?
Same with mint, you are not sure, except you are not expected to keep any valuable amount on a mint, once you have 5000, 10000, 50'000sats on a mint, transfer it to Phoenix, Breez, Zeus or your full node with lightning, then when you have 100'000, 500'000, 1Msats on Lightning that you don't need for spending, swap it on-chain on a cold storage with key properly secured.
It's just a matter of habits and education.