As White Queen of the Hellfire Club Frost was able to mask herself and her Hellions from detection from Xavier's Cerebro and Magneto and Apocalypse etc... my modifying their brain engrams as revealed during her breakdown over the Hellions deaths in Uncanny X-Men.
And that was before her Diamond Form was introduced. So what could the helmet possibly add apart from being a Cyclops/Magneto/Onslaught symbol? Is it a portable Cerebra? Is this black leather Cyclops/Emma hybrid foreshadowing something else?