in 3bet pots ppl call flop wide with pairs IP to see what you do on turn, you can get a surprising amount of folds with a small-medium turn bet, and of course they fold their pair on river if an over likely in your 3b range hits and you shove.

basically taking a line that makes them put in a lot of money while folding a lot

pf is ok given the spot you stated, very high steal % without much 3betting happening yet by us. Basically a high success rate for the 3b bluff. Even so I'd probably wait for something that plays better postflop