Initially, I thought the same thing until a salesman explained it to me. The inner ring is actually a convenience for manufacturing purposes as they can make fewer capsule sizes and adjust for coin sizes via the insert. It's basically how they keep the cost down and can quickly ship orders. (very Lean Mfg'ish)
Though the question I forgot to ask was if the insert would could eventually breakdown and create a problem for the coin. I'm assuming that the answer is no and I hope it is as I have my more valuable coins in them with inserts.