$27 15/30 Hit Set Villain Shoves Turn Can I Call to Ship It?

[Q..]

I don't understand call on the flop, just push it there. Only reason to call flop i can think of is that you think he folds flop ,but pushes turn, so he pushes turn, and you fold...
And really for a flush draw thats really strange and expensive check raise play, i agree that its usually 2 pairs which we are well ahead on the turn.