Reasons:

1) Aesthetics and exercise value.

2) Approx half the weight of powered scooters

3) Powered scooters are outlawed in some places, bikes are allowed almost everywhere.

4) Easy to walk a bike in a crowded place, and easy to lock at a bike rack, fence or pole.

5) Didn't need to convince the Admiral (maybe this should be #1)

6) Quiet and no need to carry gas -- and if I run out of "steam" it's because I need to excercise more.

Electric vs. gas: The electric ones being quiet, there is no way to dependably charge the batteries unless we stay at a dock, and we usually don't. I wouldn't want to add any more big recharge loads to the boat's electrical budget. BTW this is also a major drawback to electric dinghy outboards.