Not to belabor the obvious, but she gets noticed for a few reasons. First, she does excellent costuming work. She not only creates highly detailed costumes, but does the full-on hair and make-up specific to that character. Second, she's attractive and has a good figure. I'm not saying that every guy who sees her starts drooling at her cleavage, but let's not deny that she does use her appearance to her advantage when designing/wearing her costumes. Third, she gets into her character. When she puts on one of her costumes, she inhabits the character, changing her posture and facial expressions to match. I haven't seen her in all her roles to say how accurate each one is, but she's definitely putting in more effort than standing around.
She's been designing cosplay items for over a decade now, and been selling items from her own booth at shows for about half that time. From what I can gather, she pretty much makes her whole living doing cosplay and cosplay-related things, like selling personally designed items.
That's fantastic! To be able to turn cosplay like that into a career is phenomenal! Definitely not something everyone can do, but that it's viable at all astounds me.
But it also makes me wonder how is it that one person can do that when another, seemingly equally talented individual can't. I mean, I know Han is not alone in her cosplay-slash-costumer-as-career thing, but for the number of people who do really excellent cosplay, you'd think more would be able to make the transition to a paying gig. Like, there are a number of great, insanely talent artist out there who like comics and, while they might not be drawing for Marvel or DC, can they still make their living off their art.
Kudos to anyone who can turn what they love into a living. Even more kudos to someone like Han who's basically forging an entirely new path with her work. I'll have to keep my eye out for her and people like her to see how business models develop with this aspect of fandom.