I find they're pretty ubiquitous where I'm from. I had one in every apartment I've lived in. I don't have one in my house though.
I know a lot of people will just dump a lot of food waste in there. After struggling with it, I started just throwing out all of the waste and using the garbage disposal for the small bits of food that would normally get caught in the sink strainer.
Now that I'm back to living in a place with no garbage disposal, I do miss it a little. The sink strainer is a bit gross to handle. But it's also pretty nice not having to maintain the garbage disposal so it all evens out.
Very small things, but still things I needed to remember to do. Running it every day. Making sure to clean it every week. (Ice or garbage disposal cleaner) If I didn't clean it, even after running it every day, it would smell. When my partner would clog it, I would have to fix it. (Again, it took little time.) Making sure nothing fell in there before I ran it every time. I would often find my measuring spoons or a fork in there. (It doesn't really seem to matter to my family how many times I tell them not to leave small things in the sink.)
I recognize this is very little and it's basically nothing for most people, but sometimes I have a very hard time keeping up with things and the garbage disposal is very out of sight, out of mind. The sink strainer is very visible.