For many people, if you're not using some kind of adaptive equipment, you must be OK. I'll bet that in many circumstances, it would be more valid and credible to be a quadriplegic in a motorized wheelchair than a person who has cognitive challenges due to a traumatic brain injury or stroke. How could you have a disability, you look fine.
Since the Americans with Disabilities Act was signed into law, any person with a disability is entitled to civil rights. The price, especially for the folks in the hidden disabilities group, is the stigma that will inevitably fall in their laps when they have to announce that even though you can't see it, they have a problem that requires a special approach for a solution.
As I have written many times, being successful at living when you have a disability is knowing all you can about your condition and then discovering all the techniques you can use to accommodate those limitations. Even according to the Dirty Harry Callahan [a Clint Eastwood character], "A man's got to know his limitations." [or woman]. Once you know them, work around them; be creative, get help, figure out a way.