I actually really like that helmet. It adds a bit of diversity to the primaris force, which, if I'm being honest, is a bit bland.
You know, this is the biggest issue with SM. They're so uniform! With Chaos you have characters with horns sticking out their nipples and heads coming out of their eyes. Each unit is pretty varied. Tau have a zoological encyclopedia of units to chose from. Eldar aspect warriors all look quite different.
But SM...well, they all kind of look the same.
I wasn't impressed with the helmet until I read your comment. Now, although I remain unimpressed, I see a good reason for it. Although personally, I'd rather stick some Calgar Honor Guard helms on the jump pack guys.