Pin Connector 62462 vs 75535 I wonder what is the purpose of the slot in the 62462 pin connector? What can it be used for, beside from help with part separation?

Part 62462 (2005-present) is newer than 75535 (1995-2008), but the slot makes it more ugly in models, for my taste. You need to rotate the slot towards some contruction part that will hide it, but it is not always possible. On the other hand, the groove at the 75535 end is not desirable sometimes also.
I have seen one possible explanation posted in a comment in this question:
Why does the pin recess on the Technic turntable continue to the edge of the part?

User Joubarc states:


  Another good (if maybe more subtle) example of this is the pin joiner
  which now has a slot in the middle. That slot is similar to the recess
  seen in the other parts, in that it simplifies the moulding process
  greatly. (The previous version required two sub-parts to be assembled
  together, which is even worse than a mould with moving parts)


If this assertion is true, then the slot exists simply to streamline the molding process. If you look closely at the top-rim of 75535 in your example image, it is easy to make out a very fine line. Perhaps this is evidence of two sub-parts being assembled.