Saw a guy in the gym doing this as his workout, moving back and forth between the bench and hack squat machine. Lots of time between sets. Older dude anywhere from 40 to 55.
Normally I'd think anyone doing this was a moron, but this guy was in decent shape and fairly strong for his size and age. I happen to be a follower of the Franco Columbu school of thought: "if it works, it works no matter what anyone says." But still alternating between bench and hacks?