Power and noise - old server hardware is not something you want in your home.

Commodity desktop cpus with 32 or 64GB RAM can do all of this in a low-power and quiet way without a lot more expense.

The problem is with the form factor, not the server hardware per-se. If one buys regular ATX motherboard that accepts server CPUs and fits it in regular ATX case, then there's lots of space for a relatively silent CPU air cooler. 2690 v4 idles at less than 40W which is not much more than a regular gaming desktop with a powerful GPU.

The only problem in practice is that server CPUs don't support S3 suspend, so putting whole thing to sleep after finishing with it doesn't work.