Take a look at this cover.
At first glance, a variation on the Starship Troopers theme of armored infantry.
Note that two of the three soliders are also wearing helmets.
The third one isn't, presumably because she's the protagonist, and we have to see her face to identify her.
It's not the brightest move to go into combat without protection to your head; but, again, there is "marketing logic" to doing so.
Now take a look at the "alternate" cover...
1) She's looking in one direction and firing in another (hopefully not hitting one of her comrades in the process).
2) She's shooting left-handed. The other cover shows her as right-handed. Is she ambidextrous?
3) Where's her helmet? There are no other characters present, so just having her name on her chestplate should cover identifying her character!
4) Slight problem with my solution to #3--she doesn't have a chestplate! What sort of idiots armor every square inch of a body except the head and chest?
Hormonally-driven idiots who want to see a buxom woman's cleavage--even if it gets her killed!
Curiously, on the inside of the book, her armor comes all the way up to her chin, and she has a helmet, which she wears when facing the enemy!
It's sloppy cover art direction, it's misleading, and it's gratutitous.
This is exactly the sort of prurient-interest image an up-and-coming Wertham would use to start another Seduction of the Innocent crusade!
Don't the creators believe that their story and characters are good enough to attract the target audience without resorting to this sort of bullsh!t?
And, the real killer is that this is a relatively-mild example of this sort of thing!