Correct. Here in Germany, I have many contacts with iPhones (you can see the FaceTime option in contacts) but no one, I communicate with on a regular basis is using iMessage. WhatsApp is #1 by far (not that I like it, but that’s what it is).
For my closest family contacts like my 70+ year old parents or my aunt, Telegram is #1 as they mainly use iPads and Android Tablets and there is no WhatsApp-App for tablets. My aunt does not even own a smartphone but uses Telegram for messaging and sharing photos with her friends and family a lot on her Lenovo Tab.
iMessage is really not a thing in Europe.