Who knows why we do it?
I've fully detailed the interior of a 1/72 Italeri DC-3.....all the seats, curtains, overhead luggage racks, galley, head, full cockpit..........and you can only see a little of the cockpit and the tops of the seats thru the windows............
I felt pretty good about the work I did - but I'm really the only one who saw it. Pretty silly, really.
I'd say we do it cuz most of us are perfectionists who just feel they need to "get it right".