Cargo Bikes

yes, esp for kid carrying IMO.

I find 350w perfect for my usage (1 kid and sometimes haul heavy-ish loads of around 30kg)

Madness?

I’d say so. I imagine it would absolutely demolish batteries / wear all your drive train parts super fast etc.

I went to compare it to the Bosch cargo line motors which are plenty powerful, but it seems they have stopped using ‘Watts’ and instead measure power in torque / Nm.

For perspective you can get 200-300kg up a hill with these.

Also worth mentioning the maximum allowed wattage to be considered a legal ebike is 250w iirc.