There are indeed a multitude of these places popping up. Some are not legit. Their purpose is to get you to contribute your music, then steal it for another site you don't know about. Thus, they pay you a little, and keep more for themselves. Every so often, I play "whack a mole" with them, as an intellectual challenge while knowing it's a losing battle.
I am not commenting whether this site may be legit, except to say I checked for music from several colleagues I work with whose music would normally be found on a music site, and they are not on this one.
An advantage to using the more established sites like CD Baby or Amazon for your music is that they decide which other sites are legit, and handle all the accounting so you don't have to. CD Baby pays a lot better than Amazon, and if they decide this new site is legit, my music will show up there eventually.
CD 2-minute preview. Studio recordings of tracks composed in Band in a Box.