I would think that bentonite is way to heavy for the worms to even crawl through. I don't think there would be much nutrition or bacterial action due to it's heavy nature. We use bentonite to line ponds to waterproof them and it works very well. Hopefully someone with more knowledge will give you a more complete response.

Do a search on words like 'cat litter newpaper tired of cleaning the catbox' here on this forum. there was a link about a kid who did a worm catbox because he was tired of changing the litter for...i think it was like 7 cats.

good luck!!! I think 'yesterdays news' was the brand that's best for the worms.

will it hurt the worms? I doubt it.

Will it result in a finished material you want to add to your garden? Not unless you have very sandy soil in need of clay.

Will the worms 'process' it? I doubt it as there is nothing in it to encourage the worms to eat it.

In others words sure you can add it, but it seems unlikely to contribute anything beneficial to the worms or the end result unless you have very sandy soil that needs clay to aid in water/nutrient retention.

We use SwheatScoop (ground wheat litter) for our 8 cats. The poop goes down the toilet and everything else goes into the compost piles or the worm bins. We had tried Yesterday's News earlier, but found out that it took forever to break down when used as a mulch - even after a rainy winter we found plenty of it on the ground that was indistinguishable from new. Don't use bentonite unless you need to add clay to your soil.

I would be a bit careful using any used cat litter, even if you flush the poop down the toilet. Cats carry a disease (toxoplasmosis?) that is not killed in the composting process and is trasmittable to humans. I therefore wouldn't want to put compost like that in a vegetable bed or anywhere that it might get into the human food-chain. I would even be careful about handling the worm compost for fear of getting sick. If the cat takes any medication to rid her of worms, guess what, it will kill your worms too.
I do have a worm bin just for dog poop which I am trying as an experiment. I haven't yet harvested any compost from it and I don't grow any vegetables so I am still unsure what I will do with the finished product. Right now it is out in my backyard where the nightime temps get down to freezing, so not a lot of activity happening there while my "supply" of dog-poop grows beyond the worms appetite to eat it. I can't blame them.