Or to put it more clearly - how to transfer your data into something that you can physically misplace...
If this sounds cynical, remember that I can lose spectacles, soup spoons, sports jackets, hats, and heirloom books. In fact, if I put my mind to it I could lose a 1996 Ford Ute in the spare room.
But that is not the point of this product. It is a repository - 240 GB of storage - for digital files from your computer or your camera. Once you no longer need or want them on the memory card of your camera but still need to keep them until you get home, you send them off to this tiny black square. In they go - via the socket at one corner:
There they stay until you extract them later. And look at the physical size of the thing...
What price the Epson and Canon portable hard drives with screens, speakers, and big batteries we were selling in 2008-2009? People were taking them off on overseas trips in an effort to duplicate and download the files from their DSLR's after each day of tourist shooting. Hard work after a hard day of hard work.
Another school of thought says to keep all the memory cards you shoot as separate entities until you return finally to your home computer facilities - I follow this line myself now that cardsat the speeds I use are cheap enough. But if you are currently depending upon some violently fast card to capture multiple images you may not want to get more than one or two and opt to use one of these caches instead.
The third school says shoot only as many photos as you need with correct exposure in the smallest possible file size possible. Frugal minimalist imaging. People who do this probably live in clean white houses and own no more than 30 books. I cannot tell you where to meet them as I have never seen one come into a camera shop.