A. There are people that have poop towels even without using a bidet. Blegh! B. I still use TP to dry after using my bidet but the amount used is waaaaaay less. I have a cheap bidet that just has water but there are fancy versions that include fans to air dry. I imagine that feature might eliminate TP completely.
Don't pass up the opportunity to have sex or take a shit: you'll always regret it.