The extra space is really useful. When we hired a MK7 on holiday when they first came out we weren't impressed by the boot (smaller than our old mk5 boot) but didn't know you could lower the floor. Without it we couldn't fit our two suitcases in the boot - which easily fitted the Mk5 boot.
The GTe and R don't have the option to lower the floor because of battery/crazy 4wd stuff.