We had 6D measurement with several (big) grippers, gripper change system and partially vision system on the robot. In my opinion this was a waste of time and money, because the grippers have to fit at more than one gripperparts, if he is twisted from a crash, you can't 'repair' it with measuring. But the customer wanted it, don't know if it was ever used to correcting something after a crash or so.
It's a bit fiddly to setup, even the specialist from Leoni needed one complete day for two grippers.
On KUKAs they need 4 tool_datas for one gripper, that's a bit strange, but can be changed with a bit more programming skills than the Leoni template programmers had.
Think it is good for welding torches, glue nozzles or similar, where one single tcp is decisive.