It’ll effect performance. It will need to be always on. It risks having interaction between your normal applications and server services. Also all your eggs in one basket if something goes wrong. That said it shoul be fine. Just take frequent snapshots and backups for important data

Is power consumption a consideration? I want my self hosted server on 24/7, so a low-power single board is much more economical for me.

Also, are resources a problem? If your game is maxing out your rig and some batch job on a self hosted service starts, that could be annoying — or it could be a non-issue, just depends on your usage both as a desktop and a server.

What do you want to self host? To learn or experiment buy a cheap old x86 box. I get mine at goodwill auction. Otherwise desktop is good if you want something that needs more compute and that you’d spin up as needed vs always on.

I mean, I use a regular desktop computer that I just installed Ubuntu on and plugged it into an ethernet cable in the closet and closed the door. Now it’s my server. RGB and all.