Not waste; an opposite of it.

First, you can't exactly buy a PC like this. At best you can pay to have one custom-built for you.

Second, this is an exercise of some hardware skills, both mechanical and electronic. The machine, besides being a good working machine, is an excellent conversation piece, including conversations with prospective employers.

Third, it may be a rewarding pastime. If you think that pastime is useless waste, and productive work should consume 100% of your awake time, (re-)watch the movie called "The Shining" as a part of mandatory job safety training.