Building would be objectively cheaper and more fun than having someone else build it for you, but there are reasons why not, and mental health is honestly the big reason for me.
And sure, building a PC is like Lego, if Lego had a bunch of tiny pins, wires, circuits, transistors, capacitors and diodes that can be broken and cause hardware issues at any moment. It’s absolutely fine for people to seek a pre-built or have someone build it on their behalf if they desire, and I wish the hobby snobs of Reddit would say that.