"What gets published for the world to see adhering to GEDCOM standards is a completely different topic."
Yes and no. YES because the GEDCOM is for sharing between applications, but NO because if someone asks for a solution that does not translate to the GEDCOM then the solution is lost to transfer (into FTM or out of FTM).
So my example is that I do use the STATUS for a child connection to a family and the information is lost to FTM. If FTM understood and implemented the GEDCOM standard then they would have implemented the STATUS feature and people would not be needing work arounds to say "this is not a proven link to a family".
Just like "WebLink" it is great to have it as a field in the FTM-DB but I already have weblinks in my NOTEs, PAGE/Citation information and CALN/Repository Locations field. Why have another place that does not translate in/out of FTM via GEDCOM?
These "extra fields" causes user lockin to FTM forcing users to lose data when they attempt to move away from FTM or use other applications to do things that FTM does not do well.