For me, it may be that the toilet paper roll needs to have the open end away from the wall. I don't want to reach under the roll to take a piece! That's ludicrous!
That or my recent addiction to correcting people when they use "less" when they should use "fewer"
Sure the sentence works, but now you've lost the distinction between more of an abstract concept and a concrete implementation. It wouldn't be wrong to call both material and mui a design, but in conversation it can just be useful to have a little more distinction between the two without having to go into the details explaining it.
(also damn i should have chosen a better example than material, their naming is pretty confusing)