Funny enough, subsurface is kinda' the reason I switched to Linux. My computer is over 15 years old, and I really wanted to wipe it clean but I had no way to re-install windows if I did so. Even though it was BARELY usable, I was holding on to it because it's the only way I had to download dives from my dive computer (I think I got the last one sold before switching to wireless uploads). Eventually, I found out that subsurface existed, and then I took the plunge.
Subsurface was kinda' my first exposure to the idea that somebody(s) would take any time at all working on software that they couldn't either sell or use to collect sellable data.