Research suggests the more bikes out there, the safer it is for all. Fatalities and collisions remained constant as use quadrupled. Motorists are perhaps more aware, and that cannot be bad.
Adding assisted bikes will probably mean more less experienced riders . There is a ebike store on my commute and I have dropped by, checked them out and considered them as perhaps an option as my body ages. Beyond my situation, it is not hard to imagine where they might offer options to a variety of needs.
Increased mode share is not a bad thing, in general. However I remember when the CB radio went from a pleasurable hobby and a useful tool to absolute dysfunction owing to hordes of overwhelming numbers. Safe facilities are rare enough throughout the country, would every MUP or separated roadway be overwhelmed as a result?