If i remember correctly, back then even some sysadmins were even fired over it because of the usage of resources. It also sprouted some weird projects on how to distribute all those unused cpu cycles for other things.

Yeah I remember a few projects attempting "grid computing", where the idea was distributing application threads across CPUs over freaking ethernet.

Have to say that would be a fun puzzle to try and optimize for, but network latency would always be a hard physical constraint no matter how fast. Maybe some niche use cases, but then multi-core CPUs and GPU processing really took off and I guess it just got even less useful.

And yet, distributed computing only became huge when people could earn / generate money off of it. Seti / Folding walked so that bitcoin could run?

I can't really condemn people trying to earn money with their cpu cycles, but good causes sometimes still exist.