If you're truly replacing bike trips (and the cyclist isn't eating or showering* more than they would riding a scooter), then the scooter is less eco-friendly.

If you're also replacing an occasional car trip, the scooter is likely a net win (an electric car has something like 300-500 scooter batteries in it).

*The energy used by a single hot shower will get you most of the way to LA (from San Francisco) on a scooter.