Document usage of TopologyElementTags in CellSetExplicit API

I spent quite a bit of time trying to track down a bug that was caused by mixing up the parameters to CellSetExplicit::PrepareForInput. My intuition is that From=Cell and To=Point should produce a connectivity table that would map cell ids to the associated point ids, but instead I got a table that does the reverse mapping.

I can't find these parameters documented in either the user guide or the source code. Can someone who is familiar with how this works (and, ideally, the rationale behind the choice of names/mappings) add a few sentence describing how this mapping works and why?

As a broader discussion, does anyone else find this convention confusing? Maybe it's just me, but I see this as a very rough edge in our API that will trip up new/potential users.