People like tangible, easily understood, and (typically) one-dimensional metrics for assessing product quality. Look at: Mega-pixels for cameras back in the day, and sheet thread-count. Neither of those things is telling the whole story nor are they even directly related to quality. But people latch on to them because they’re a single number, and easy to compare.

No one understands what’s actually inside a car and what physically distinguishes a good car from a bad one, so they latch onto the one parameter they can actually see and touch and understand: body panel alignment and paint quality.