These are popular with a subset of DIY builders because the laws aren't really enforced, so they can get a small electric motorcycle that passes as an e-bike while not adhering to the requirements for a vehicle that powerful.
Some will try to claim that if you set the bike to the lowest power then it's legal, but of course they'll quietly switch the power to whatever they want when riding.
Fwiw you wouldn't ride around town at 3kw, that would be ridiculous and dangerous. The default power level is "1" (out of 5) which assists with around 180-250w.
Fun trail bike though (helpful on the uphills, for someone who doesn't typically enjoy that part).
In BC, Canada, there is a maximum motor power limit of 500W for e-bikes. I am not sure if switching (or locking?) the e-bike to power assist level 1 would qualify.
Depends on the engineering requirements of each system. Maybe? Price point, materials, durability, manufacturing volume, size and other factors definitely affect the weight.
It seems quite shortsighted, weight makes a huge difference. My brother recently bought some 75-80lb steel-framed e-bike with small diamerer wide wheels, and couldn't even make it 30 miles with pedal-assist before it died. The last 10 miles his speed plummeted from 15-17mph to 4-6mph at most, and this is for a very strong (but out of bicycling shape) guy. On unpowered bikes he is much faster than me, and I'm not a slouch.
I tried riding the steel thing with no battery and it was not pleasant at all. Compare that to my LunaCycle, even at 50lbs total it's not that bad to ride with no power.
Is it mostly clueless people (like my bro) falling for "It has a battery so heavy bike weight will not matter"?
I suspect DJI is aiming for legal bikes that established bicycle manufacturers can sell.