If that results in skills useful at work, or for finding work, that's a nice but entirely secondary benefit. The more important benefit is burnout prevention - because I too "don't get paid to do the interesting things that first attracted" me to software, or science and technology in general.

> I'm just boggled at how many people appear to find it unimaginable and unrelatable that a technologist likes technology enough to mess with it for fun, even after work.

Me too. I sometimes wonder if I'm not missing out, but try as I might, I don't enjoy the "normal" stuff as much as I enjoy intellectual stimulation. I also sometimes wonder if this isn't because my eyes just don't get tired from screens. I can look at computer screens 16 hours straight, and my eyes don't get dry or itchy. I had co-workers who had to use saline drops at work, and I can understand if they didn't want to look at any screen when they got home.