It is part of the definition for intellectual disabilities though. From [1]:
> An individual is generally diagnosed as having an intellectual disability when: (1) the person's intellectual functioning level (IQ) is below 70-75; (2) the person has significant limitations in adaptive skill areas as expressed in conceptual, social, and practical skills; and (3) the disability originated before the age of 18. "Adaptive skill areas" refer to basic skills needed for everyday life. They include communication, self care, home living, social skills, leisure, health and safety, self direction, functional academics (reading, writing, basic math), and work.
Being bad enough at math that it impedes day to day life is not sufficient to qualify for intellectual disability under the ADA but it's one of the major factors.
I think the point is that even capable humans are often in situations where they are functionally disabled - like when they're really exhausted or inebriated or mentally/physically overloaded - and all of these accessibility technologies are helpful in those situations. It's not about the ADA definition but humans in practice.
[1] https://www.eeoc.gov/laws/guidance/persons-intellectual-disa...
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.
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”.
I think likely we would still need some kind of formal recognition, but it's interesting to ponder.
Most people wouldn't call it a situational disability because they don't know the term. But it's a common term in relevant fields.
I'm not partially blind just because I can't see with my eyelids closed.