How realistic timewise is plugging e-bikes into plain old wall power ? Is it any improvement over trying to charge a e-car from wall power (i.e. all-night plus) ?

Depends on the battery size (which depends on bike weight).

For a pedelec (actual e-bike meant to be pedaled), wall charging with a brick/wall-wart works fine. That's how they all work, at least any that I've seen. Some have removable batteries to make that easier, but the high-end models tend to have the battery wedged into the down tube and not removable (with complete disassembly of the bike).

For an e-scooter or light e-moto, wall charging should work fine, but it won't be fast. YOu're looking at 3+ hours to charge. Fine for most commuters and running errands, but not suitable for a delivery vehicle - they'd have to hot-swap batteries (or complete bikes).

Not sure about large electric motorcycles - there aren't that many out there right now. I'd guess similar to e-scooters, just with an even longer 10-80 or 0-100 charge period.

Ebikes from wall power works well. Also at ebike size, batteries are swappable, so you just get two and charge one while you're using the other one.