Yes --- Convenient, doesn't require refilling boat tanks, reduces use of onboard pump, "fresh" city water
Gee, what's NOT to like???
No --- MUST, Must, Must, must turn off water at dock pedestal
WHENEVER leaving the boat, even to go up to the head on the dfock or visit as friend. If you don't understand whenever & must, this is NOT for you. It requires discipline. The ONE time you do NOT do this...
Boats have been known to sink from failed pressure reducing water inlets (which is what it is BTW); doesn't move water in onboard tanks.
Your boat, your choice.
I've had boats since 1983 and have been boating since 1955. I wouldn't touch one of those things with a ten foot pole. If I'm too lazy to fill up my water tanks, I need a new hobby.