TGP's...what's the point?

[GregBoston]

I'm new to this, but from my reading it sounds like TGP submission can be unprofitable because the conversion rate of that type of traffic is so low that the bandwidth can cost more than you make from the surfers. And if you submit to something like The Hun successfully, it can be an awesome amount of traffic you receive.
So I'm wondering if you can submit the hosted galleries that sponsors offer? Will TGPs list them?
Or what about free bannerless hosting, though as far as I can see you can only promote the sponsors' program on those sites?
In both cases you're using the sponsors' content and bandwidth. Sounds like a no-risk proposition.
Or do the TGPs want unique content? Or they don't mind the sponsors' content, but it would be a miracle if you were the first one to submit it to them, since everyone does it? Or maybe the TGPs make their own galleries for that free content so that their affiliate codes go in it?

So I'm trying to figure out this TGP submission stuff, and any answers to these questions would be appreciated.