I’m in the UK. My friends and I all use WhatsApp because it’s easy to create groups and to share photos, videos and documents with the group or individuals. Even the non-techie folk can use it without issues (apart from “oops wrong group”, which is always entertaining). I find the calling feature useful because the cell phone signal is very poor where I live but I have good WiFi. Overall a simple app that does a few things well.

I hate Facebook, and it is me no end that WhatsApp is Meta.