You can store your photos on it. Since it has a internal hard drive, anything on it can be lost when the drive finally fails. Its just part of a storage solution, and someone without a robust backup setup can lose all their images.
Just to store photos, IMHO it's not a great device - unless you have no PC, although if you have a compatible camera you can just put it on the device and have the photo downloaded. On the other side, it just supports only USB 2.0, and CF cards (no CFast) - depending on the camera(s) you have it can make it obsolete soon.
If you think to use its other features a lot - i.e. using it to display photo/videos on a TV, use its apps, etc., and have no other device for that, depending on the price may be enough attractive.
For photo storage a couple of external disks, and preferably a DAS/NAS with some redundancy are better solutions. A single disk is always a higher risk.
Even the EOS Utilities does a decent job of downloading photos and organize them automatically, for simple needs.