I qualified expert many times with the M-60, M-240, and M-2 machineguns. The M-60 with it’s slower rate of fire was easily controllable off the bipod. I loved shooting that old gun. The M-240 was better off a tripod or pintle on a vehicle. The M-2 needed a sandbagged tripod and preferably a T&E mechanism. Shooting it free hand off a pintle can be done by someone that’s trained on it a bit and has the aptitude. Some people just can’t do it.
In a shoulder fired weapon though, full auto is generally a waste as you said.
There’s been a version of this on the market for fifty years.