eMMC is basically just NAND + a controller in a single for simple interfacing and management.
In the case of this specific device, they do not provide on board storage, but they offer the next best thing; a header for attaching what would be used as on board storage in a marketed device so it would be interfaced the same way ect.
They also provide a microSD slot.
Pros of this device, the chip is a beast in its class, very good performance, though, depending on what you're emulating it may/may not be sufficient.
Cons: This is a pretty obvious software dev board, so don't really consider doing hardware dev. I'd need more info on what you're looking to do with it to give you more info.