Aside from a couple non-US friends, I know no one in the US who uses anything other than straight SMS (and Apple iMessage). I'm sure they exist but certainly not in the circle of people I communicate with.
For whatever reason, chat seems to definitely encourage tribalism. The last company I worked for eventually bought into Slack because so many people WOULD NOT use anything else while a lot of us were like "ANOTHER chat app??" because we were perfectly happy with Gchat which we had as part of Google Workplace.
I know there are some historical reasons for non-SMS because of text pricing outside the US but everyone I know in the US would look at you funny if you wanted to use some special app for texting.
There's definitely different circles in the US. My circle of friends and family is on Whatsapp. More than 99% of my communications would be through WhatsApp.
iMessage is very much a US thing. Most of the Non US people or people with international connection exclusively use messaging App ( whatsapp, Telegram, Signal)
