I definitely get where they're coming from though. It seems inefficient to have all these services running on separate hardware where each service might only be using 25% of the capability (not necessarily in OPs case with the Pi3B) of the device and needing three separate electrical outlets to do some real basic computing.
I've been very casually exploring Proxmox on a micro Optiplex but haven't had the time or need to jump in head first quite yet since things are still working. The real downside is that your single piece of hardware becomes a failure point for everything but as this is just home hobby stuff and not a big business, it's not really that big of an issue.