Yep, I've bought a lot of music over the years because of bootlegs. Hell, many bands would never have been as big without bootlegs.
Some of my favorite artists I wouldn't have discovered without downloading their albums, but the Touhou fan community thrives because most of the material is easily found online.
If I had both the money and a reliable dealer to work through, I would buy hard copies of Iron Attack's albums, the games themselves (despite not being able to use them on my MAC as-is, I'd still like to have them for sentimental reasons), and Tzeentch only knows what else.