That sounds pretty fair to me. Very few regular bikers go faster than 20-25. Especially with more weight, like delivery or cargo bikes, and also especially with the e-motor support there is a lot of weight and power behind those bikes.

And bike lines are usually built for "regular" use, not high speed. All the curves, break distances etc. get planned with around that speed and not a whole lot more.

The original purpose of supporting disabled people who can't use a regular bike is still served and people don't have to be afraid of maniacs going 50mph in places where "common sense" would already advise them not to. If you're using a cargo bike, that also still works and you get not so gently instructed to watch the speed with your cargo.

Maybe they could do something where to use a bike lane, it has to be speed capped. Idk.