While sometimes it was a pain, I do think I would like the 2nd layer of protection that authenticating into ST with a 2nd Touch or facial scan is a good idea. I cannot find a place to turn it on. When I open ST it just opens.
I don’t know how to do it with Face ID, but I use the screen time method to lock some sensitive apps on my iPad since it’s on my wheelchair and always unlocked and if I’m taking a nap one of my health aides might be able to access it.
I have not seen Face ID or Touch ID offered in the new ST app.