I was intrigue with the massive ad placement of bux.com here so I tried googling around.
My take is ... they sound similar to a bank, but parang virtual bank on your mobile.
You can withdraw your money anytime so no hassel, pwede rin online payment, and free sending every month when your in their free zone.
Found this in youtube.
https://www.youtube.com/watch?v=vkmmG_mBw2o