I do some offhand shooting even when going to the range to bench-test stuff, but the biggie here in Montana, as Shrapnel pointed out, is shooting burrowing rodents offhand. (He likes to bet a Coca-Cola on those shots, but since he works for a Coke distributor he gets them at a "discount," so there's no much pressure on him either way.)
But I also simply must mention that I once shot a big game animal from a benchrest, a mule deer doe that wandered too near the old farmhouse where some of us were staying one year. There was a bench in the yard.
Almost once shot an Alaskan moose from a benchrest once too. Actually, it was an all-purpose piece of plywood, nailed to a tree along the banks of a small river in a hunting camp, used not only for testing whether rifles were still sighted-in after the flight from Dillingham, but filleting salmon and other stuff. The bull moved at the last moment, and I had to move down to the river bank to take the shot.
