Mine are too, but I still use ziploc bags. For me they are more to organize and separate various types of gear and clothing. They separate clothes that are clean, from those that are lightly soiled but can be worn again, and from those that are dirty and are not to be worn again without laundering. They also allow air to be squeezed out of the individual ziplocs to save space. They make it much easier to find stuff without digging through a pannier to find an item on the bottom. They make it quick and easy to grab the toiletries and food to put them in the bear box.

I really find that panniers that are one big pocket with stuff split up into ziplocs to work much better for me than using panniers with multiple compartments. I felt the same way when backpacking and the practice carried over nicely to touring for me. The pannier's waterproof-ness is a nice plus.