I would ass-u-me the difference would be a crown sits ON top of your head while a headband goes across the forehead in some manner (unlike the little girl headbands that pull your hair back... (actually, BD crowns I have seen ARE like those headbands with a vertical crown looking thing sticking up.... assume the headband part is more secure for one to wear if one is actually dancing as opposed to sitting on a float or something

)
& crowns DEFINITELY scream 90's (not that I am one to talk.... I absolutely LOVE & wear mostly the "vintage" am cab belly dance look!!!!)
I think if it suits YOU AND your DANCE then by all means.... wear it...
but I could never be a crown girl.... for oh sooooo many reasons!!