As many others have said, reptile carpet is a pain to clean and sanitize on a regular basis. I couldn't imagine it smelling that great after awhile either.
I keep my bps that are in my rack on paper towels or newspaper. It's cheap, and easy to clean.
For my display tanks I use either aspen or reptibark. I tend to like the reptibark more as it helps with humidity moreso than the aspen.