“That begs the issue of whether or not assault weapons have any utility." No, it does not, especially not from any entity of the national government. The right to keep & use firearms that is explicitly protected by the Constitution “shall not be infringed.” Therefore, it is legally irrelevant what the nature of the firearm is.
So, instead of focusing solely on something that is legally protected by the Constitution, how about spending some time on the violence, which is nowhere protected, except in cases of self-defense. E.g., why has the number of people confined in mental hospitals dropped to 5% of what it was in the mid-50s when the population has almost doubled? Has the rate of mental illness diminished by a factor of 40?