What’s the catch? This is the best deal I can find on the internet by a fair margin. This seller has an amazon store page as well and seems to have a good reputation on both. The seller claims its a new HDD from a reputable brand and offers a 5 year sellers warranty.
Edit: I have had 2 out of 3 ordered drives fail on me from this order. The seller was good about offering a refund. But I wouldn’t use these drives without at the very least some kind of redundancy if not a full backup.
Hey at that price it’s at least not a huge loss if they only last a few years. Best not to keep anything you can’t replace on them anyway.