I have other concer
CME appears to be positioning these weenies for
1) exposure to the equity indexes versus ETFs
2) spreading opps
3) ability for customer to withstand volatile periods.
That said, they are completely fungible with their parent contracts. But the real fun is that they will allow short and long positions to be held simultaneously (ES/MES, NQ/MNQ, etc), but that will come only with relatively high cost. The ability to hold neutral, and the fungibility probably lends itself into the existing option products in some way, at least I would think so. But that's not my game.
I do think these weenies will be successful. Hell, I can see myself holding a couple for overnight or plain ol directional swings. Even a limit move wouldn't do massive damage to a guy like me! But don't get me wrong... I don't like these products longer term! If you can spell CME and you have $50, you, yes you, can become a futures trader! What can possibly go wrong? And what kind of changes to futures trading comes after?