I think the thing that has really been exciting for me about getting into 3D printing is the increasingly rare experience of having a fairly complex machine that I am in charge of maintaining, upgrading, and fixing that truly require regular maintenance. unless you've got the garage space and money to get into cars, opportunities to do that have mostly vanished during my lifetime.
sure, you can build a computer, but the goal of building a computer is to have to open it up and check things as infrequently as possible. as for anything else in your home, manufacturers have spent the last few decades slowly ensuring that any mechanical or electrical device in your home is as hard to open up as possible and basically impossible to service yourself and built as cheaply as possible that you'll just throw it out.
there was a time when, if, say, your toaster broke, you might reasonably be able to get out a set of tools and fix it. I'm reasonably certain any modern toaster will be designed with the goal of making that impossible. it's nice just having something that doesn't fit that ethos. also, I'm pretty sure if I tried to make a little Ralsei figurine with my printer, it wouldn't even finish the first layer.