There are a few reasons like their extended software support and their built in text recognition and translation features.

I don’t live in my home country and this is very very useful.

Since everyone in America uses iOS and iMessage only, I’m kinda locked into iMessage for communications.

I know there are other messaging apps, but no one has any of them. There are people I communicate with just a few times a year and I can’t ask them to download an app just to occasionally chat or catch up.

I also use very few google services. In fact if you don’t count invidious I only have a gmail account which I use for no personal stuff like Netflix accounts and stuff.