HEMA biggest attraction is probably that it's European Based. This brings to mind right away the image of knights, honor, valor, heroes, battles, warriors, and other awesome conceptions and ideas that we may have about that time period. It's difficult to compete with that, especially if people are seeing it as an ethnic identity that is a part of their ancestral identity. With TMA we have non Asian embracing Asian Cultures. With HEMA you have people of European descent embrace, European Culture. By that definition alone I should have more pull towards Capoiera than Chinese Martial Arts. I think the only reason I don't is because. I already know my historical culture and I have a natural interest and enjoyment of exploring cultures that aren't mine. I think this is the exception and not the rule. Most people's comfort is with their own because it's something they can identify with. For people like me, we like to play outside of the box and our life often reflects that willingness to go beyond our own culture.
I personally think HEMA is cool and of value, to the point that I hope other cultures will look back and to the same with some of their forgotten fighting systems.