It completely depends on what your specific circumstances are, and something is always better than nothing.
(Also, you aren't getting ECC RAM at this price point, no matter what.)
What's a good use case for this? A house with a few laptops, a desktop and one server. Everything uses the server as their datastore. The server runs ZFS, but even ZFS can run out of luck, so you send over a snapshot to the backup device every day or three. It's insurance.
