They already do this. James Harden, notoriously. It sucks to watch and defend, but is effective.
I don’t think this is quite right. You get 5 (6 in the NBA) per game.
One way to use them is as a buffer for playing aggressive D. If you never foul, you’re not playing hard enough.
The other way is a desperation strategy. Dude going up for a dunk? Rake him across the arms, 75% X 2 shots is better than 99% X dunk.
I wouldn’t call either unfair, just attempting to maximize your chances on any given possession.