I have a very beefy desktop for the first time in over a decade (maxed out Mac Studio) and I am wondering is there any real downside to having these services run on it?
My desktop gets shut down, rebooted, crashed, wiped and reloaded, and otherwise abused as I get thoughts.
My home server has been the same (don't worry I run updates) for a couple years, chugging along, sipping about 1/4 the power my desktop would take.
In the beginning of your self hosting journey, the opposite might be true. You might want to try 300 things, and that's hard to do if you're trying to get work done on your desktop.
1. My 12-year old, former top-of-the-line laptop is much faster than my 3rd-gen Pi when periodically ingesting and indexing JSON into a PostgeSQL db, I suspect slow IO and limited memory are to blame.
WoW (wake on wife), worked pretty well from the office, but I seem to get a little bit of latency and packet loss. Now I work from home, so I just get up and hit the power button on the more powerful machines.
My shock with compute power was when I got the Pi 4. It was faster than the AMD e350 I was using for backups except for disk IO. The E350 was not a powerful machine new, but I didn't realize how far we had come.
A USB 3 enclosure brought it to a level that was good enough the entire mini ITX build was pointless to keep around.
E.g. you can't restart your desktop while your roommate is watching a Plex movie. Or your VPN stops working because your roommate's cat walked on your keyboard while you were on vacation.
A pi/old computer is a physical box you can put in a corner and you can be sure the physical network works if it is connected.
Especially for DNS. Like, your system reboots for an OS update and now the rest of your the devices on your network have connectivity issues for an hour or so. Or you have a hardware issue and now you lack both the infra and the workstation so getting things up and running again becomes triply annoying.
I've found a raspberrypi/orangepi to work just fine and it doesn't matter if the main computer is on, I'm upgrading to a new system, or traveling between work (laptops). It just sits in the closet and does it's thing using a tiny amount of electricity.
I like the VM rather than running it directly on the Mac because it's trivial to copy the VM to another computer when I want to change hardware. Obviously, your services will be unavailable whenever the host machine restarts.
It's reasonable to assume that the 115 W on a Mac Studio will never be hit on a workload that could be supported by a RPI...so you're looking at an extra $10-20/yr to operate the Mac Studio.
The biggest issue is just the upfront cost, since of course the Mac Studio is proportionally expensive to its capability.