Almost all the trails here are multi-use: you’ve got hikers, bikers & horses. Trails are already busy enough without adding a bunch of new riders on e-bikes. At least, that’s the thinking.
Whenever there are conflicts, it always seems like it’s the mtn bikers who get screwed. We’ve had lots of trails closed to biking because the hikers & horse people have complained. I’m sure it will just get worse if e-bikes are added into the mix.
That’s the real reason for being wary of them, IMO, not extra weight or trail erosion. Although, more bikes and people riding longer/farther (because e-bike) will obviously impact the trails too.