I tried to figure out what a homelab was once, but it seemed to just be people who enjoyed having a lot of fan noise at home so they could assemble VLANs for no particular reason.
Other people just enjoy the blinkenlights.
You don't have to do that. Mine is a pair of Ryzen 2 white boxes. They are dead silent and don't put out much heat either. All my network gear is fanless too.
I do automation, so I use mine for dev/test against the stuff I am automating. A lot of it could run in the cloud, but that gets expensive real quick. Especially when I am working with a VMware stack.