There is a literal 0% chance a single person in the entire history of our species has made the decision to switch to different software because shift-clicking the scrollbar didn't do what they expected it to. On the other hand, plenty of people are drawn to applications that look visually cohesive and are not an eyesore; not only because humans appreciate aesthetics, but also because visuals are an information channel and thus having non-obstrusive graphic design that guides your eyes to what matters has a very practical benefit.