There's a lot of reasons people who are a little more into mainstream tech would want Linux.
If you do embedded, those systems often run Linux, and it appeals to anyone who likes the idea of one standard platform for everything, so you might as well use it on the desktop. Especially with RasPi work, which is similar enough to Ubuntu that it really does seem more or less unified.
It's also free, and can run on old computers.
It doesn't have any commerical incentives to leave out features, so a large linux distro can support every protocol, file format, and filesystem with no hacking and fussing and buying expensive compatibility apps.
If you do embedded, those systems often run Linux, and it appeals to anyone who likes the idea of one standard platform for everything, so you might as well use it on the desktop. Especially with RasPi work, which is similar enough to Ubuntu that it really does seem more or less unified.
It's also free, and can run on old computers.
It doesn't have any commerical incentives to leave out features, so a large linux distro can support every protocol, file format, and filesystem with no hacking and fussing and buying expensive compatibility apps.
It supports lots of old windows stuff via WINE.