I'll just throw out that until relatively recently, a lot of airplanes still had ashtrays. Antiquated seat design doesn't imply a set of rules. "If I'm not supposed to smoke, then why's there an ashtray?"
Seat design has been largely static while people have gotten bigger, seats have gotten closer, and laptops have become a thing. On cheap European flights, they mostly have removed the buttons. I personally only ever use the button if nobody's behind me.
I’ve heard that the continued presence of ashtrays isn’t a vestigial design feature so much as an intentional holdover, so that anyone who breaks the “no smoking” rule still has a safe place to put out their cigarette.
And that's probably why they need to constantly remind all the passengers that there is no smoking in the bathroom, and please don't tamper with the smoke detectors in there, we really mean it, please ignore the emergency-use ashtrays.
Seat design has been largely static while people have gotten bigger, seats have gotten closer, and laptops have become a thing. On cheap European flights, they mostly have removed the buttons. I personally only ever use the button if nobody's behind me.