Chances are enterprise drives will last far longer than 5 years easily in my experience, but in my opinion 15% off isn’t enough to justify not having a warranty. I see those sales often enough on legitimate drives.
Enterprise drive sales aren’t restricted in anyway, you just need to buy them from a reputable seller. I personally would avoid Amazon, there are tons of “deals” like the one you found on there and they don’t make it obvious. A legitimate seller example - www.connection.com/product/…/41308811?cac=Result