Maintenance is a different story, but the difference really isn't that big. Dye transfer can be a problem on lighter coloured seats, but if you clean your seats on a regular-ish basis using a mild detergent, you shouldn't have any issues. Black obviously hides most stains and stuff much better, so you'd probably be able to get away with not cleaning them as often.
Black leather also absorbs and retains more heat in the sun, so parchment coloured seats will be easier on bare skin, and the interior ambient temps will likely be lower compared to that of a black interior.
In this case, Parchment is only a color name. My Parchment cloth has been easy to keep, doesn't show dirt easily, and doesn't stain or rub off color from my clothes. I can't imagine leather would pick up stains either. I find it a refreshing, attractive look vs the black leather in my last CX-5.