Why do you presume that it should be easy enough for them to use without training? Keyboards are a pretty simple technology, and serve as a subset of the primary interface to most modern AI models, but training is still required to use them well. A user who's never learned proper keyboard skills will type much more slowly and with much more frustration than you or I can, and that will have meaningful impacts on their ability to perform tasks requiring a keyboard.
It's just a kind of training that's receded into the background as "normal", and that many of us who enjoy recreationally typing out comments on the Internet self-taught.
I didn’t learn writing, speaking, research skills from typing out comments on the internet. I was required to use hand written note cards up until I graduated high school (heck even had blue book tests in college). The first paper I ever wrote was hand written. When we did start using computers, none of those skills were altered by passive internet chatting.
So AI training is going to be a basic communication course? Because AI is sold as being easy to use without training and as modeled after existing human social constructs, hence artificial intelligence.