I think flatting the flop is considerably better than shoving. No better hand is ever folding, so even if V1 rarely calls with worse (because our flat looks so strong, for example), the few times he does it makes it better than shoving. Once he calls the flop he's not folding any turn, but he won't realize that often enough to make flatting bad/obvious.
Edit: I think our flat can look like 76 often enough that it's not 100% guaranteed we have a set. A shove makes a made hand much more likely.
