[rsynnott]

In general, I don't routinely carry a credit/debit card anymore; only exception is when I'm in the US, where it's still somewhat common to find swipe-only setups. I do normally carry a small amount of emergency paper money; if I'm visiting somewhere where paying with paper money is normal/preferred/mandatory (notably Germany), I'll have more.

But for normal usage, why would I carry around a card to tap on terminals when I can just tap a phone on them instead?

I think the US is possibly slightly behind the curve here because mobile terminals are a fairly new thing there; they mostly became common with Apple/Google Pay, so about ten years ago. In most of Europe, chip and pin became largely mandatory around the turn of the century, so people taking your card out the back to process it was no longer an option, and they pretty much had to have a solution that could come to the payer anyway.