Would the Mac Mini actually idle at that wattage if it’s open for connections? I doubt it, it’s probably more like 10W, which is generally the range for those smaller AMD MiniPCs or NUCs.
If it’s 10W, that’s a $20 savings from your NAS w/ a desktop CPU (and probably a discrete GPU, unless it’s running an APU). I can get 4% easily on savings, so I’d only need a $500 savings vs the Mac Mini to recoup that difference every year ($500 * 4% = $20). So if you already have an old PC, use that instead of buying a Mac Mini, and you also won’t have to fight macOS to do what you want.
But in terms of money savings it would rarely make sense, as you need to make it back during the time you run the system. If we assume 6 years lifetime then it would only make sense to pay $120 more. But yes, I’d also go for a system that runs regular Linux :)
I don’t have a Mac Mini, but for always-on systems, the idle power consumption can become quite significant.
If you pay 0.30$/kWh, running your old 100W gaming PC all the time would cost you 263$ per year. My NAS is 45$ per year…
It also depends on what you need/want from the machine. The Mac Mini doesn’t have any HDDs and can’t run a regular Linux distro, for example.
Would the Mac Mini actually idle at that wattage if it’s open for connections? I doubt it, it’s probably more like 10W, which is generally the range for those smaller AMD MiniPCs or NUCs.
If it’s 10W, that’s a $20 savings from your NAS w/ a desktop CPU (and probably a discrete GPU, unless it’s running an APU). I can get 4% easily on savings, so I’d only need a $500 savings vs the Mac Mini to recoup that difference every year ($500 * 4% = $20). So if you already have an old PC, use that instead of buying a Mac Mini, and you also won’t have to fight macOS to do what you want.
I do think it can achieve that while waiting for network packets (see e.g. https://www.anandtech.com/show/16252/mac-mini-apple-m1-tested).
But in terms of money savings it would rarely make sense, as you need to make it back during the time you run the system. If we assume 6 years lifetime then it would only make sense to pay $120 more. But yes, I’d also go for a system that runs regular Linux :)