Very true. A psychiatrist buddy of mine (since passed) had a whole bunch of full-auto weapons, and a place on his property where we could shoot them. You can run through LOT$ and LOT$ of ammo really quickly. And hit nothing with most of the rounds. Burst fire is also fun, and far more practical.Honestly, the only nfa item I would be interested in owning is a suppressor. As you stated earlier, machine guns are fun to shoot, they are also expensive to feed, especially for someone like me.
Suppressors are excellent. In the event that you ever need to protect your home, you're not going to be wearing ear protection. There's no reason you should be forced to go deaf to stop a home invasion robbery. They also improve the speed and accuracy of follow up shots, by decreasing muzzle flip.
I think something like the Maxxim 9 would make an ideal bedside gun, or duty gun for LEO's.