If you’re interested in home automation, I think that there’s a reasonable argument for running it on separate hardware. Not much by way of hardware requirements, but you don’t want to take it down, especially if it’s doing things like lighting control.

Same sort of idea for some data-logging systems, like weather stations or ADS-B receivers.

Other than that, though, I’d probably avoid running an extra system just because I have hardware. More power usage, heat, and maintenance.

EDIT: Maybe hook it up to a power management device, if you don’t have that set up, so that you can power-cycle your other hardware remotely.