well heres my reasoning. a flush draw has a higher chance to hit than a straight draw. no matter what. its a simple 9 outs to 8. now when you start calling raises searching for one of your straight cards (and there are only 6 in the deck that will comfortably complete your straight), you are in the exact same position that you would be if you were playing over cards.

now i agree it might be wise to play it because it is deceptive, but i hardly think one should play it simply because of the straight possibility.

i think to play this well you would have to aggressively take control of the betting. that way if the flush doesnt hit (and the straight doesnt either) you can try and force folds prior to a showdown. i would say bet the flop small and entice a raise, at which point you reraise hard. you want to make it as clear as possible that a flush is the only out the others have.

i believe the only way to play this is if you have implied odds, not only do you have to play with the chance of comfortably hitting your straight, but the chance that your opponent will also miss theirs. this cannot be played like a regular straight (check/fold) draw.