Distractions for the masses
Nah, just kidding. It's a feature that "should" be on Mint. It is already a glossy looking DE (Cinnamon) and for the user to be able to make it even more shiny is actually pretty cool.
After all, Linux is about personal preferences. Personally I am fine with a somewhat sober or minimalist interface as I am distracted very easily.
But there are tons of users who will find their way around this 'styles' thing and will create magnificently looking themes.