This would be great but how on earth would we get people to comply? We can't even get people to wear masks in stores right now without throwing a tantrum. People would like lie like crazy regarding their weight. Heck, my driver license is 25lbs lower than I currently am.
I guess you could alleviate the embarrassment factor by making it a total passenger + baggage max so people could weigh themselves AND their carryons at home before they arrive to confirm and offset anything.
Interesting idea though!