I read some where that it does add more overhead, I had problems just exporting the deform bones only as the hierarchy gets all messed up… end up making another skeleton that had the right hierarchy and was constrained to the rigify deform bones… have to make two animations strips not to difficult… eventually will make my own rig… but for testing purposes using the rigify…
Also I think making deform only skeleton helped with the cloth APEX tool…
Thing I’m finding out now is the arm and legs have four bones instead of only two can’t use the IK functions without either IK bones or removing the extra bones… but I think the extra bones are used for twist…