cinaed666

It’s completely valid for them to do so. Their Top Level Domain meant for their purposes.
Even though it’s rarely enforced, many TLDs have specific purposes and conditions against abusing it for unrelated purposes.
There are many others to pick from.

https://friture.org/
I used to use this one when I was still mixing live music on analog gear.
I had a linux laptop running with jack2, on the headphone out of my soundcraft desk connected to my usb audio interface, visualing the input. (Which would be the single instrument I had selected or the entire desk output).
I’m sure it would work well for locally playing music as well.