When I discovered this option a little while ago I was happy to find that it worked as you'd hope. It hid all the regular bones but not big or dragon bones. This made a lot of sense to me as I think most people who are trying to get prayer exp would focus on burying big/dragon bones. Lastly some people would also collect dragon bones for selling on auction house.

Then the other day it got updated to hide all bones, so now you've gotta toggle between them frequently. I propose this either gets changed back or add another option to the list of options where you can disable regular bones only.