You're very sure of your opinions, vfr! I'm left wondering how you might believe the extra kilos carried by an ebike are so very different from the extra kilos carried in pannier bags, given you're sure I've not very much experience of riding an ebike?Sorry to sound patronising, but how much experience do you have of riding an Ebike on the road? From your comments, I'm going to guess not very much. Anybody with any amount of practical experience riding normal electric bikes would know how much better hydraulic disc brakes are for such bikes. There's absolutely no comparison with rim brakes, which are maybe acceptable on light-weight road bikes, but are a liability on a 25kg electric bike with a heavy rider on board.
I wouldn't suggest that from your comments, you've little practical experience of setting up bike brakes so they're working correctly - perhaps we've just had very different setups on bikes we've ridden?
Replacing cables with hydraulic pushrods definitely improves brake performance as frictional losses are minimised (but increases complexity and when used with disc brakes, introduces the danger of losing all braking down a long hill), my points were regarding disc over rim brakes however.
I've ridden ebikes over a relatively short distance - not quite 2000 miles - and have found neither type of brake is fussy about the type of kilos they carry. Both will lock up a front wheel under 10mph with my 80-90kg plus 15-20kg of bike, on a dry road.
I'm fully aware that's all that matters to most, my post above was directed at keener ebikers who might be interested in what the sales blurb for disc brakes fails to mention.
There's no doubt disc brakes are here to stay, they're even fitted to supermarket bargain bikes - how much is due to fashion and profit versus real world gains for bikes used on roads is an interesting debate. The bigger the disc, the better it works.