It makes sense because you are unlikely to run production workloads at home.

So you don't really need a half a terabyte of RAM and a 220v power supply for the world's most expensive electric space heater.

Instead people are most often interested in developing infrastructure-as-code or testing deployment strategies or doing tests to see what happens when outages happen. Logging, metrics collecting, simulating network failure, simulating software attacks. etc.

In most of those cases having a number of smaller machines makes more sense then trying to emulate a small datacenter on a one or two big ones.

In practice I think most people end up with 2 or 3 'big machines' for times when they do need the Umph or want to have a big storage array for their "linux ISO collections". Then having a number of Pis or HP mini desktops in arrays is just for good fun.

If I want to simulate full blown workloads and benchmarking then I can just use AWS or Azure for that. A lot cheaper to lease verts for a evening or two, then buy big machines and leaving them idle 99.8% of the time.

So, now I am left with building another system and I need to decide form factor. Is this going to be headless or run a GUI of some kind with a monitor attached? Should I buy a big ole tower case or move to a 6u or 12u rack system. I want more VRAM and I need as much PCIe as possible. One thing for sure is that I don't want it to be Raspberry Pi based. I have two Pi4 collecting dust that were fun and impressive for what they are.

I saw these mini racks and wondered how they would work with an extended ATX board. Could these be useful as some kind of "open air" or mining type case where you simply bolt stuff on. Definitely going to investigate, so while the exact application of mini-racking pi's is not my jam, I am thankful that it was brought up.

On the other hand, I don't go to the trouble this guy goes to. I just have a cheap mini PC plugged into Ethernet sitting on top of my router.