On a three speed 28" from ca. 1985 btw., weighing 12kg with side dynamo, lights, mudguards, rack, and a wirebasket fixed with a bunch of cable ties on top of that(for my back pack).
I'd much rather do that on a proper ebike and not on a escooter. I've got drivers licence already, bureaucracy shouldn't be in the way of registering ebikes as appropriate.
I'm sorry, but that's just not true - again, I used to cycle absolute loads(several thousand km a year) and "sustaining"(doing it for a long period of time without getting absolutely destroyed) 50km/h is extremely hard, you need to be a pretty good cyclist and on a good road bike.
And no, you don't need to be keeping up with traffic, in cities or otherwise. Don't see why you think you should.
I had bike that could do 50km/h and it was just a bit too slow. You wanna be comfortable overtaking cars, not just be squished in-between.
An ebike is for the same roles as a human powered bikes, and no human can consistently move at speeds that are comfortable for overtaking cars on the flat or uphill.
Escooters, if anything, should be even slower as their geometry makes emergency braking impossible, but a 25km/h, 250W limit for everything is an acceptable compromise to reduce regulatory burden.
If you want a stand up scooter that produces kilowatts and does 90, then it's also an electric motorbike (or motor scooter/moped where that's a category) and should be held to the same safety standards.
So like, almost no one who cycles/commutes from time to time then? Don't get me wrong, 25km/h isn't particularily fast, but I'd struggle going at that speed for more than few minutes, and my wife definitely wouldn't keep up. I used to cycle loads when I was younger, on a proper road bike that kind of speed is nothing. But on a hardtail or a city bike? It's actually quite hard! We own an e-bike and I think the 25km/h assist limit is spot on.