A debit card can be used as a credit card at a CC terminal. No PIN and no transaction fee. I don't think you'll find many people typing a PIN into a CC terminal in the wild.
AFAIK it's mostly in the US that using cards don't always require PINs. Here in Canada I have to enter my PIN whether it's my credit or debit card, for every purchase at a CC terminal. The only exception is if I'm using contactless payment. This was also true in Europe last I checked.