It runs full android. In fact, it’s way more powerful than a phone this size has any business being. You can even play (some) games on it with no performance drops at all.

Usability with large fingers is slightly less than normal, but honestly not bad at all. I use a T9 keyboard (pictured below) and it’s great and I type relatively quickly. I have the option of quickly switching to qwerty but T9 does the job well and it’s fun. screenshot

Edit: I did turn up the system font size, which makes things a bit tight sometimes, but honestly it’s very usable without doing that as well.