Very practical
I considered this product to be a gadget, but I changed my mind after trying it out. I'd bought it to try and give a 2nd life to discarded hard drives (I replace them after 7 years, as a matter of principle, but that doesn't mean they're worn out).
In practice, it's very useful, when upgrading hardware, transferring data from an old drive (which I've just done), or providing a simple and inexpensive backup/archiving solution (a hard drive at a friend's house, away from home, for example).
Easy to use and not restrictive.