Lots of assumptions and generalisations being made here..
My kid rides a modernish Norco hardtail but he commutes too and from school on a Pure e-scooter.. let me explain why
For the first 3yrs of secondary school, he walked to school, ladened down with books.. we live in the bottom of the Porter Valley, his school is up between Bents Green and Whirlow.. the only road up there is Highcliffe Road, the bottom section has no footpath, Highcliffe Road is steep af.. steeper than 95% of roads in the Peak District.. there are houses on the left, allotments on the right.. (pull it up on google maps, you'll see what i mean) cars park on the left..
Riding up the hill would be a struggle for most but just about doable if there was no cars but you have to stop behind the parked cars to give way to the traffic coming quickly down the hill.. setting off again, up the hill with zero momentum into oncoming traffic in the dark is dangerous af.. i never see anyone riding it.
To avoid Highcliffe Rd, my kid used to take a detour on foot, through the woods and through the allotments alone in the dark.. he would arrive at school 40mins later, with his school shoes (and often socks) covered in mud..
We got him an e-scooter (i know the legality is a gray area but it's a lot less worrying than knowing your 12yr old is alone in the woods in the dark) ..now he rides up Highcliffe Rd because the acceleration from 0-17mph is instant, he can get past a line of parked cars in seconds, it has a front and rear light, indicators and 4x reflectors, one on either side of each wheel.. he rides up to his friends house at Bents Green, puts his e-scooter in his friends garage, takes off his waterproofs, hooks'up with the lads and they all walk to school together, he arrives dry with his school shoes free from mud.. it has little effect on his fitness levels, he hikes in the Peaks, skateboards, plays football, tennis and lacrosse.. he's fit af!