Yes, that's one function. Montmorrilonite, in either the sodium or calcium forms has a really cool physical structure. It does a job similar in concept to activated carbon, but very different chemically. Whereas activated carbon acts by van der walls forces and weak attraction with huge surface area, montmorrilonite acts by having all these areas in its crystalline structure that attract many types of harmful radicals and substances in the body. It's a sort of living clay. You can use it, for example, to bond radioactive and heavy metals, removing them from the body. And yes, it does provide trace minerals, but think of it like this: when you take sand and put it in acid, what happens? Sand remains, but some trace imperfections might be weak enough that the acid dissolves some ions. Now image if that sand grain was "porous" and had these holes inside to accept acid and to accept other types of stuff. Well, in that case, some sand might break up, making it smaller, and some might bond bad stuff to the sand grains.
This is just an analogy, trying to explain how it works. It's not a plain element fed as a supplement for trace minerals. There is some bioavailability from the trace elements, but the bigger role is as a sort of detoxifying, life-enabling clay.