At 20 or so pounds it is way too heavy for an infantry rifle.
It also requires batteries. Battery technology is not very good yet, heavy and short-lived.
Finally, while I have not seen it stripped, it appears to be a very complicated system. Infantry weapons should be simple. The M-16 has too many parts for my way of thinking (yes, I know it works).
I would much rather have an AK, an M-16, an M-1, an M-14(best choice), or even a lever-action 30-30, rather than one of these gee-whiz gizmos.