I read this brief exchange several times before I figured out what was being asked and answered. Allow me to add my interpretation.
Q: Is J2ME useful for writing games?
A: J2ME MIDP was designed for mobile devices like cell phones so it will only be useful if you are writing programs for mobile devices.
It's worth noting that the Wireless Tool Kit J2ME simulator should run most MIDP games just fine on a desktop PC however the user experience will be less than compelling. It would be better to stick to J2SE.
I think it was the oddly worded question that threw me. If the "is" was "be", then it might have been clearer. Mark's clairvoyance is better than mine.