Well, if you are the most dangerous bounty hunter in a tight battle suit, looking like a fucking lizard out of it seems more realistic than looking like a model.
Samus in the official art looks squeaky clean and perfectly healthy, not like a murderous bounty hunter who ruined her stature by spending too much time in an exoskeleton and regularly replaces sleep with combat drugs while starved of human contact and facing numerically superior opposition.
Pic related is a space trucker. She looks like shit, talks like shit and has <1 fucks to give (Hollywood version). Now imagine she had to wear a helmet as part of a combat suit.>short hair is much easier to stow and maintain
She also hardly ever uses her back muscles because she is always suspended in a suit.>stands crooked like a teenager who spends his days sitting in school and at home
And she has almost no human contact for long stretches of wake time and suffers combat stress all the time.>abuses stimulants leading to discolored eyes
Not saying it's pretty, but it is a rather thoughtful design.