To do the flashpoint and see what it's like. That's the only reason. Of course you're going to get extremely low exp because you don't need to do the flashpoint for any other reason. There are still dailies around your level anyway.
Why even bother waiting around and NOT leveling if that's your main concern? Just ask yourself that since you brought it up. I gave you a perfectly good solution just for that reason.
My point is that if you can get a group in a short amount of time, more power to you and good luck. If you can't and no one's bothering to do it then why look stupid just asking around for 30 minutes or more on end when you could be enjoying the main aspect of the game?
I definitely don't wait around when I can't find a group. But It's pretty ridiculous when I get 5XP from doing Black Talon/Esseles for the second time when I'm only level 15 and it's a 10ish flashpoint. (I know I could go do Hammer Station at 15, but that's not the point) Trust me, I'm not talking about being level 50 and wondering why BT gives me no XP. I did Foundry at level 42, I believe it's about a level 38 flashpoint, Why does a measly 4 level gap mean that I get practically nothing from it except XP from killing mobs? I The mobs weren't grey, in which case I would understand, and the bosses were still a pretty decent challenge, it's not like we ran through the place and powered through it in 20 minutes.