Phasma’s armor is coated with chromium obtained from a yacht that Emperor Palpatine owned while living on Naboo, according to the Star Wars: The Force Awakens Visual Dictionary. It both reflects radiation and symbolizes power, which she shows off with every calculated step. But that armor—which is unlike that of any other stormtrooper—had to come from somewhere, and considering its source, we can understand why it’s so special.
Does Phasma’s armor also have a hilt to hold Oathkeeper?
Brienne of Tarth is so bound to her duty and mission to find Sansa and Arya Stark that she changed her name, joined the First Order, rose up the ranks to command a battalion of stormtroopers, and will kill enemies and civilians alike without hesitation when ordered. Now that’s dedication to the cause.