Dealing with multiple computers is a pain (slow boot time and/or more power consumption and multiplied effort) and more expensive in most cases (you still need the minimum requirements of each part, but now there’s the rest of the each PC to get too).

I did it for power consumption; one small low power computer that’s on 24/7 for NAS + providing some services like home assistant, and a powerful computer for gaming, photo development, etc. I ended up being too lazy to boot up the powerful computer most of the time so I was doing less of what I like to do with it and my time spent on the computer was slower. I switched back to one do-it-all computer and I’m much happier.

The only reason I would want a multi-systems setup is if I need to run some things in the background that would make the computer unresponsive or unusable for some interactive tasks (e.g. local AI inference or training, video transcoding, heavy data transfers, …).