I got the steam key, but I had no place to enter it on Steam, so I had to buy it again. There was literally no way to use the key - no place to enter it, no option offered. To wit: I had made a whole separate steam account, which uses the same e-mail as my itch.io account, so I don't think that was the issue.
I know it's not a lot of money, not at all, and I was happy to buy it again, but it's just the principle on the thing.