I’m not sure if it’s true for all EU countries and banks, but in general you don’t put in your PIN every time with contactless. The card usually works for a number of transactions without a PIN, often up to a certain limit, after which it asks you to insert it again.
It is arbitrary and random. Some machines will ask for it and others won’t. Some automated machines will refuse US cards altogether. Wait til you’re at a tollbooth entering the Autoroute trying to use all your US cards, and none of them are accepted.
I’m not sure if it’s true for all EU countries and banks, but in general you don’t put in your PIN every time with contactless. The card usually works for a number of transactions without a PIN, often up to a certain limit, after which it asks you to insert it again.