F4 only has 9 frames hit advantage. During those 9 frames, the opponent can only block. Throws are around 14 frames start up (I can't quite remember), so if you time the move to start up on the first available frame, it will come out at a point where only the fastest moves in the game will beat it, I.e, Cassie's flip. Armoured reversals will beat it too. Lackeys EX Uppercut knocked me out of a similar set up I was testing the other day (I think it was the d1-tick throw option select, which should work according to the frame data, but armour beat it.)
The problem with this strategy is that it requires you to be frame perfect. Too quick, the move won't come out, too slow and you could be hit out of start up. Lag makes this worse. That isn't to say it won't work, but don't depend on it.