Depending on the machine this might cost you more in electricity than a VPS. 100watts continuous costs something like $7/mo in a fairly low electricity cost region of the US.
That would be assuming the machine is on 24/7 and only be used for Minecraft. A lot of Minecraft management systems allow the Minecraft server to be shut off when no players are on which would limit how many resources are being used on the machine 24/7 too.
Overall I personally prefer a VPS or dedicated server but I don't think comparing it like you are is 100% fair.
I don't even bother with playit.gg - just forward a couple ports on the router and pass out my ip. Only time my dynamic ip changes is when I lose power, and if I've lost power the server is down for "Maintenance" anyways.
Or you can just use a dynamic ip service and use that URL anyway. That would keep the IP up to date. That is what I have done for years and it has worked well.