In order for worms to be able to "eat" rock phosphate, it first has to be broken down by bacterium and then worked on by fungi hyphae that are attached to the plant
roots.
This makes it not so useful for worm bins since it has to go through a minimum of two breakdown steps prior to the worms being able to digest it.
If you want to give it a trial then by all means do so and keep a note book, you will also need the laboratory capabilities to test the worm poo for phosphates.
Worms do not (contrary to most beliefs) process soil, they do process microorganisms and "red wigglers" do eat vegetative matter, much more so than "earth worms" who live much deeper than the wigglers.