This is an inherently inefficient design, where that inefficiency means increased 1) battery use and 2) tire wear.

From a cyclist’s perspective, this is fundamentally a stopgap product for “curious” customers dipping their toes into e-bikes. I don’t say that necessarily to criticize it. There’s a place for a product that someone can put on any old bike and see if they want to buy a more expensive long-term solution. But that doesn’t make it a product I’d recommend.

The tire wear problem is significant enough that there are heat resistant tires specifically for this type of drum application (designed for old-style indoor trainers, not for use on the road), because use on a drum will cause premature wear for normal road tires.

Destroys tires, very limited range/power due to poor power delivery from motor to tire. Parasitic drag when coasting or battery is dead.

Limited power delivery, horrible in the rain, prevents using fenders

They aren’t reliable or efficient.