What kind of bothers me about e-bikes is that in the alleged quest to "save the environment" or whatever drives it all, it just creates another ultimately disposable consumer item made up of expensive, environmentally-questionable materials. Lithium for batteries is mined in terrible conditions, much of it in China and the Andes. Copper, steel, rubber, aluminum, etc. -- all of it has to be produced or recycled from somewhere.
Bicycles are great for the environment mostly because they have already been built. There are hundreds of millions of them floating around the planet. You can refurbish a 100 year-old bicycle to operate 90% of the way a modern bicycle does. Mopeds, to an extent, have also already been built. No significant additional plundering of the planet is required to use and enjoy them, other than one gallon at a time Dino juice, maybe a small hunk of aluminum now and then for your top end, a metal-link chain, and some rubber tires every 3 or 4 years.
To mass-produce brand-new consummables like e-bikes, without some kind of infrastructure where spent batteries can be easily recycled and replaced, thus making the the rest of the bike last for decades rather than years, does not quite hit the mark for me. Mass public transportation, biking, walking, etc. has much less impact. But I guess if e-bikes get people out of automobiles, that would be a worthwhile goal.