In Europe, I usually get a receipt and can write the tip on top of that, than I'll pay everything and get the real receipt, including the tip

Why should I even need to check into a stupid app, I don't even want to have?

It's just so much easier to see the real paid amount at the end

Edit: and just saying, I've been doing that all my life, doesn't make it better
"That's how we've always done it" is the thing that stands against progress

If a system is better, than it's better - and we can compare

So, what I'm up to:
Maybe I'm missing something here, which makes this blind trust better in some way, but nobody told me how