Original Star Wars movie "A New Hope" is based on contrasting esthetics.
On one side we have evil Empire, with its bleak wedge-shaped Star Destroyers, flimsy and bare-bone TIE fighters (not resembling any known earthly aircraft) and of course faceless stormtroopers and pilots (plus Vader). Whole look of Empire is based on fictionalized mixture of Japanese Empire and Third Reich from WW2.
On the other side are good guys - Rebels. Their main fighter X-wing has distinctly earthly look (wings above everything else, especially with foils closed ) , pilots look like US pilots, ships have more rounded and organic shape, soldiers have faces.
This contrast is not accidental, it is well known psychological effect that people subconsciously associate something familiar with good, and something strange and foreign with bad. In this case, with clear visual difference, Lucas didn't have to slow pace down pace of the movie to explain which side is good and which one is bad. From opening shots of Imperial Destroyer chasing CR90 corvette, and stormtroopers killing Alderaanian soldiers, we already subconsciously drew that conclusion.
Later however everything had to be explained, so we got somewhat un-plausible stories how Rebellion secretly financed and purchased almost completely different equipment than Empire, instead of just relaying on using captured stuff.