I have one in my Santa Fe and it comes out looking really nasty. As someone who drives their car as a mobil office I think it's a good thing to have, especially because I suffer from Asthma.
For the average user, I'm sure you could just leave it out and it would be fine. My dad is driving his Windstar without it.
My aunt hasn't had it in her car from 15K KM, and now the car is approaching 300K KM.
Profit center to me, but for those who benefit from it (like me), I think it's a good thing...