I have to admit, I'm still learning all this :)

But from what I can tell...When you post directly to the community you have the option to either post to the community, or the blog. The community stuff doesnt go on the blog unless you resteem it.

That's the first thing I've learned :)

The second thing is that you can cross post to different communities as well, for more exposure...

To be brutally honest, this is what I'm focusing on....The image here:

This is where I see the biggest benefit to communtiies. The ability to find places on the blockchain that you have interest in. This is the biggest nugget for me...Hanging out with like minded people.

As for Fire-Pay.....Working on it, but this is a screen shot of the sites we have it integrated in as well: