I think it’s damn near the definition of insanity.
I’ve only oiled clays, so I can only comment on oiling chips, not specifically China clays. But oiling chips is a pain in the butt and the results are temporary. And let’s face it, most of our guests barely notice the chips anyway, so don’t do it to impress them.
As gross as it sounds, chips will absorb sweat and oils from your hands, so playing your chips regularly will have a similar effect to oiling. But what is that effect? Brighter colors when photographed under optimal conditions? I suppose. But is it noticible while playing with them under typical conditions? Maybe if you’re looking for it. I dunno. Not sure I want to play under that much light.
Do it if you want, but for the love of everything holy, don’t feel like you should.