Especially if you're an individual person with a non-raid6 / hot spare system, you might pay a premium for a lower failure rate (standalone drive, RAID1, or RAID5, for example).
Although in the year 2019 it would be pretty reckless to use RAID5 without hotspare. Or even RAID5 with hotspare. This has been true for a long, long time:
https://www.google.com/search?&q=why+raid5+stops+working&ie=...
If you're an individual person with a 12-drive ZFS RAIDZ2 with hotspare, in a file server in your garage or something, you might prefer to pay the premium to buy HGST, because what if you have a double drive failure during a three week period while you're on vacation out of the country?