It's also gotten them back into PC games, as they have more access to games through family sharing and the Deck does a great job of taking care of most of the fiddly bits of playing on PC.
I fully expected the deck to be the typical valve hardware experience for me. Something that was well built, and very neat, but would be gathering dust in a month or two. However, I think we've got more usage out of my Deck in 6 months then we've gotten out of my Index, Vive, Steam Controller, and Steam Link combined.