Going back to your point, though, would you say someone with a concussion is situationally disabled? I suffered from a pretty bad concussion last year which definitely caused a lot of brain fog for weeks. At the beginning I could barely think for a few hours. Would you not call this a situational or temporary disability? It’s certainly more than “brain fog for a day”.
Using a wrist mounted touch screen is hard if you can't use the other hand. It doesn't matter if it's because the other hand is missing, in a cast, or just holding something. So people in relevant fields talk about permanent, temporary, and situational disabilities.
You don't have to like or use the term. But arguing with people who do won't be productive.