Some people like the industrial look, for some reason, some people like to spend £300 on a fancy coloured aluminum case with less functionality and worse cooling than a £80 steel case, people like different things.
Clearly the HAF type cases are selling well, Antec want to sell more cases to those people so they need that type of case.
I'd be surprised if they replaced the line up, rather than just added basically alternative exterior's for their cases.
They are stupendously awful looking, though I'll always buy for functionality over style every time, if it was the best ever designed case in terms of cooling, layout, functionality it would be the case I'd buy. Seeing as its nothing special(it appears) inside over their other cases, which aren't fantastic, its just about bottom of my possibly new case list.