I think the decision to raise a draw has a lot of factors in it. Fold equity, pot odds, SPR, position, opp tendancies, and if the table has seen you in this situation before, but it does:
1. have a chance to make your opp fold
2. gets a little more value if you make you hand as opp will be less likley to bet/call after the flush draw hits, str8 draw scaring your opp really depends on how your str8 gets made.
3. disguises your hand (depending on opp once again)
4. depending on position, can get you a free river card if you miss turn
5. can make it easier to commit your opp to the pot

I am sure there are many other things I am missing here but still learning so there you go. The down side of course is every bet commits you to the pot a little more so tread carefully until you get a good read on your opp.

As far as IOPQ, while I can see how you find some (maybe more than some) of his post condescending I do find some really good info in them when he actually cares to post his reasoning behind his answers. With this thread I think his post is right on.....even if it is a little lacking in reasoning.