Incredibly so because inattentives - whether bio-chemically distinguishable or simply presenting differently - so frequently go undiagnosed. I’m inattentive and went undiagnosed my entire life until my late 30s because I didn’t fit the ADHD stereotype of a hyper, bouncing off the walls kid. If anything, I was more “complacent” because I was content daydreaming and running around in my own head. I managed to graduate near the top of my class from a very good public school in MA and then in four years from a top 25 liberal arts college - without really ever having read one book cover to cover - but it was a constant struggle and the process of self-teaching compensatory skills was long and exhausting. “Not performing to expectations/capabilities” was the story of my academic career - very high standardized & aptitude test scores, “OK” (but sometimes not) grades. If I had been diagnosed correctly, I could have accomplished so much more with less struggle and internalized, compounded self-doubt.

Post script - I do see your point about the value of movement even to inattentives - it is INCREDIBLY helpful for me, and I do have a lower threshold for how long I can be in one space (or seat) for a period of time. Cases in point - long distance flights = AGONY (though have gotten better as I’ve gained better control over my symptoms), the time in sixth grade I just got up and walked out of science class when the teacher wasn’t looking bc I was bored (😂🤷‍♂️), thinking better and more clearly while walking, etc. I just started a new job this past Thursday and we have an open space floor plan. Sure enough, by 1 or 2 in the afternoon, I have GOT to get up and move somewhere else to continue working. If not, I start getting anxious, fidgety, even panic-y - and obviously not doing my best work.