You are correct, I tested edge rings and they worked. At least the command is not totally useless then 
This is curious because I may be wrong but this appears to be using a similar process as that of the Interpolation mode Linear of âBridge Edge Loopsâ. And the regular set flow is similar to the Blend Path interpolation mode. Thatâs why a quick way of creating a âSet Flow Addonâ would be to delete the select(ed) edge(s), bridge the gap between the deleted loops and use Linear/BlendPath options, with a number of Cuts equal to the number of deleted edge loops. This would of course lose UV and vertex information, but would work.
