The same between an intrepid and a Sovereign class Starship perhaps?
Different ships require and spend different resources. Cost benefit ratios. You might need a huge cubes sometimes and a tiny shuttle craft another time and an entire of rainbow of Borg hijinx inbetween.
Have you ever seen those sad bastards in real life who would rather drive their SUV to the convenience store rather than commit to 5 minutes of walking? Now imagine some one thinking that should use a helicpoter for the same trip, a coulpe hundred meters, to buy eggs and milk?