What's your source for that?
My understanding is that the EAPC spec stipulates that to be legal the continuous rated power of the electric motor must not exceed 250W.
The wattage rating is pretty much completely ignored. In theory a 250W continuous motor should start overheating at 251W but Bosch mid-drive motors for e-mountain bikes are sustaining output of over 800W perhaps peaking momentarily over 900W at times. A 250W motor basically needs a 7A controller at 36V (7x36 which is about 250W) but in fact the Bosch batteries are delivering over 20A somewhere around 22-23A I think which is 828W (23x36). Yes there are some ebikes that have 7A controllers which maybe peak at no more than 11A momentarily. Those are generally geared hub motor ebikes.
I think if the EU didn't manipulate their certification for the benefit of their own industry such ebikes would have no real advantages as much of the EU ebike industry is about mid-drive ebikes but they tend to be less reliable, much more complicated and they wear out the drivetrain much quicker. They are also much more proprietary and expensive to maintain. It's only really by allowing them to have very high torque by using high current do they have a real selling point which is performance for hill climbing. Apply the same current to a geared hub motor and you can achieve similar high torque output.
Just look at mid-drive motor kits like the Tongsheng and Bafang models they often feature less torque than Bosch mid-drives but clearly state a wattage of 750W.
This 250W rating is really nonsense probably most ebikes on the road exceed it a bit or a lot. I don't see why ebikes can't be classed in the same way as e-motorbikes or power drills. If I buy a 1500W drill it will use up to and including close to 1500W. It's simple to understand and honest.
https://www.ebikeschool.com/myth-ebike-wattage/
Many gig economy ebike riders are doing shifts for many hours on the same battery, maybe 4 to 8hrs and clocking up a huge amount of miles per shift. In contrast I remember reading of a Bosch mid-drive e-mountain bike that went from full charge to depleted in 40 minutes because the rider was tackling steep ascents on the mountain bike pretty much continuously. It doesn't take genius to work out which ebike was using higher wattage. Technically it is easier for mid-drive to have high current use because both the controller and the motor are in the same housing so its definitely easier to feed high current to a mid-drive motor. Hub motors have separate controllers externally. Mid-drive motor kits have a dispreportionate amount of ebike fires. Many people don't understand the higher current requirements of mid-drive and don't fit the correct high current battery packs to those bikes which can lead to more stress on the cells and more fires. So despite mid-drive only being a niche in the market place. About 95% of ebike sales worldwide are hub motor based you get more fires with mid-drive kit ebikes. Proprietary ebikes like Bosch are designed with their own dedicated and proprietary batteries so this isn't an issue for them. While Bosch batteries have a high failure rate they do not lead to fires due to their design.