Cost is not prohibitive to everyone. Console owners are often not the type to buy an internal SSD and put it in an enclosure either. And a few TB is easy to fill up with games steadily reaching 200 GB nowadays. It’s not for me, but I can see who might want it.

Main thing I can think of is game drive for consoles. Games load a lot faster from SSDs but you don’t need high sustained speed. Mostly read-only so QLC is fine.