One thing to note is something that the Hasbro people said at this years BotCon is that TakaraTomy will often add in things to the toy designs with something future in mind "just in case"... like combiner ports, tabs or post holes that we sometimes never find out what they were for because they weren't used in its first release.
Kinda like putting in electrical points around the house when it is being built - some may never be used but they are there just In case and don't negatively impact on the overall design.