Well, to me it's all good. Whatever trips your trigger.
30+ years ago I thought that top tanks, particularly Magnums, were God's gift to mopeds. But I have yet to have one and am more than fine with that.
As far as practicality goes, no moped tank is going to get you farther than a Batavas Regency top tank, and the largest capacity step through tank that I'm aware of is a Kreidler (over 1.5 gallons).
Observation: It's fairly commonly believed that the phrase Mo-Ped was coined from the decals of the Sears AllState (a Puch MS50 by another name).
Question: Is the Mo-Ped a top tank or a step thru? They look kinda in-between to me.