NiftyKat - It's recommended that you don't start giving treats until your chin is at least six months old.
To the OP - There seemed to be a bit of arguing going on here, almost to the point of being personal for whatever reason, but in the end you have to decide for yourself whether or not you want to feed treats. I was told by my mentor, who had been in chins for a billion years, two things: Don't kill your chins with kindness and K.I.S.S. - keep it simple stupid. Pellets, hay, chew sticks, and water. I upped that to include rosehips on occasion, but that's it. I've had large amounts of chins wiped out after using supplement from a respected breeder and from a bad pellet (as did many others on the same pellet). I've learned from experience that I would prefer to err on the side of caution and not give junk food to chins.
You said it yourself - do you need Reese's pieces, etc.? Nope, neither do I. Do I love chocolate and bread and pop? You betcha. But it sure isn't good for me. We tell people not to feed pellets that are loaded with dried fruit because a chin will always pick out the "candy" rather than the pellets. In the same way, I can't seem to control myself very well with what I eat, but I can control what I give my pets. So I give them the healthiest things I can. Just something to think about.