Walking stick I have used for a long time, but it creates asymmetry if you aren't thorough enough about swapping sides with long-term use. Been there, done that. I still use them in airports or other places where i know I'm going to have a really bad time. But truth be told, I hate them. Losing the use of a hand is really really irritating. And then when starts raining and you use an umbrella, you lose use of both hands. Infuriating.

Walkers are probably ok, but I can actually walk very quickly most of the time if I'm being careful with my standing time budget, and the extra bulk makes it harder to carry more stuff. Which is frequently the reason I'm out of the house, picking up shopping etc. So a portable seat would be a win, but not without cost, so probably a draw overall.

I have considered a chairless chair, and it's spin-offs. But I have a suspicion that the weight distribution required for 'sitting' might create more problems than it solves in my specific case, and I can't just borrow one to test that theory. The thought of how people will react is exhausting too.

I was going to buy a collapsible telescopic stool, and I may still do so, but it can only address part of the overall problem. For example, if you're at a social event and everyone else is standing... you end up just being stuck there at crotch-height. Very awkward.

The best solution is the social contract. Everyone benefits from having more seating options available of various heights and configurations in public places. Notice how often at a gathering people eventually end up sitting to chat, because standing for a long time is no fun for anyone!