As Ellis Amdur notes, some folks (like me) are doing aikido with some infirmities and sharing what we can do with others who have infirmities, and I believe that is a good thing - but I have never led such a class for a single evening without being mindful of embodying to the best of my abilities, and sharing the key points as best I understand them, about the martial applications or principles our training is based on and pointing out some practical application of what we are doing.
When a student asks me a pointed question about why, from a practical defensive perspective, something is done this way rather than that way, if I can't demo it on the spot, we play with it for a while until it makes sense.
Otherwise, WTF are we doing while we work on posture, connection, kata, etc?!
and I think it is a wonderful thing. The point is to have the proper intent when training. I think understanding your limitations and exploring them, especially as we grow older and change is important.
I essentially run a "second start" program for old warriors. Many (most) of our students in my organization are former "operators" that have been there done that. They are over 40 and struggling, mentally and physically with the changes life brings them (myself included). By training in combative sport we are able to reconcile this process, explore our warriorhood, maintain relevance, and learn to grow old gracefully.
I think martial arts provides us a wonderful avenue to explore and reconcile this aspects!