A well presented cabin crew is the image of how the airline is like. We could debate for ours whether this is fair or not, but we all know it is true.
An elegant, smart, professional, beautiful uniform gives the idea of a well structured - and safe - organization. Whether in reality that's actually true is irrelevant, but that's what most passengers perceive and what most airlines try to achieve.
When I fly on EZY planes I know that I am amongst friendly cabin crews who have a relaxed approach to their work. When I was with FCA (the pink lot) pax expected us to be flirtatious. Pax who fly VS expect to be served on board by Miss Universe. My passengers these days ask me to solve various problems they have. Maybe the
idea they get is that I have the knowledge of a turist info centre and that I have the ability to solve all their organizational problems.
Every uniform tells something different, the tricky thing is to make it match with the image you want to create.