I have more than I can reasonably justify to any marginally impartial observer; but it is worth remembering that the low end of ‘rackmount’ is pretty much just “stack with standards”. Everything is the same width and in multiples of the same unit of height.
Compared to personal electronics of assorted, somewhat random, sizes(and occasionally shapes; are rectangular prisms not good enough for you now?) that makes things very convenient, even if you end up just taking the ears off and adding little rubber feet to the boxes. If it were all about full depth monsters that probably aren’t even OSHA approved to share an environment with people it’d be a bit over the top; but the more polite two post stuff isn’t (necessarily) much more hardcore than its unstandardized counterparts, just a lot easier to wrangle.
If learning etymology with chubbyemu isn’t your game, just considerthat rack mounted computer equipment is often quite loud-- not really suitable for the home environment.
If you’re willing to build it yourself and use 3U or 4U cases, it’s certainly possible to build a quiet rackmount server, and I’ve even done so for work. As a rule, the smaller the fans, the louder the server; big fans can spin slower to move the same amount of air. Thus, those 1U jobs that sound like an F-16 spooling up.
Even “quiet” servers add up, though, and If I was going to run a server rack at home, it’d have to be in a basement, garage, or spare room.
High end home audio gear is also generally rack sized as well, although if you’ve got the money for that gear, you probably have the money for a nice enclosure for it as well…
I am admittedly an outlier as well, with a half-height server cabinet sitting next to my desk; there’s an ancient 2U dell PE2950 and a rack-mount UPS sitting in it along with my desktop rig. At one point, I was using it for a 3d printer, at least until the hot end started failing on it.
You’ll also want to consider thermal management as well; while modern rack mount servers are rated to survive somewhat higher than normal air temps, they really do like directional cold to hot air movement. But that’s drifting into Hot Aisle design, which is very not something for home.
