Switzerland has mandatory registration for Speed Pedelecs. According to me, it's actually more of a blessing than a curse because the lawmakers decided not to follow EU regulations and confine us to 25 km/h. The 45km/h category requires registration, whereas the 25km/h doesn't.
In Switzerland, you need to pay for registration & plates for Speed Pedelecs but that includes liability insurance. The rules are pretty simple for pedal assist 45km/h e-bikes: a bicycle helmet is mandatory, and your drive can't exceed 1000 watts nominal output. You have to follow bikes paths that travel parallel to the road if they're available, including those shared with pedestrians (they have priority over you). Adequate lighting is mandatory, including for 45km/h E-MTBs.
One advantage to registration is that it has disproven the myth that Speed Pedelecs are more dangerous than the slower category e-bikes. Swiss statistics clearly show that 45km/h e-bikes are not more prone to accidents than the 25km/h variant. In fact those very same statistics show that people with the slower category e-bikes suffer more serious and fatal accident injuries (source in german:
https://www.mobilservice.ch/en/home...erheitsanalysen-zum-velo-und-e-bike-1576.html). And so authorities have finally understood that the max. speed of the bike isn't the most important factor in explaining accidents, and are now starting to look at "who" is riding the bike rather than the vehicle itself. Age, behaviour, and experience of the rider are considered as more important factors than the category a bike belongs to. Seniors riding 25km/h e-bikes are responsible for a significant number of fatal accidents, and future accident prevention campaigns will focus on them heavily.
Registration has another benefit: it means I can have the speed and not risk legal complications in case of an accident. I've just ordered the Haibike Sduro Trekking, and the price of the 25km/h iteration is exactly the same as the 45km/h version. Therefore, there's no incentive for me to "cheat" and hack the 25km/h version with a speed doubler.
So overall I can see more benefits than downsides to registration, as it's expressed over here.