@TheHateIsNotGood
but an idea worth running with - mefinks.
One of the many problems with the whole idea of using real passenger and hand baggage weights is when do you do the weighing? To be genuinely accurate it has to be at the gate (to capture the weight of last minute purchases such as Duty free)...and that opens a whole can of worms, for starters there goes quickish boarding, so bye bye short turnrounds, down goes aircraft utilisation and voila, up go ticket prices
Sorry if I'm teaching you to suck eggs, but for the benefit of others it's maybe worth pointing out that the beauty of the current system - statistically derived, properly validated assumed weights - is that it allows the basics to be done well before the passengers get anywhere near the aircraft, by basics I mean flight planning, fuel planning, fuel loading, performance calculations, load sheet preparation....
If instead you move to using actual weights with weighing at the gate then when does all the planning and performance number crunching get done? After doors close? If that's the case in theory you wouldn't even be able to finish refuelling until the last passenger had boarded.
This is all long winded way of agreeing very much with @Pandadunks previous comment: "Its not needed, it would be prohibitively expensive for airlines, the tech isn’t there to roll it out, no-one is asking for it."
Despite the headlines and column inches all Finnair are doing is their five year crosscheck that the assumed weights they use are valid.