Knowing how robust Jonathan's cantilever assemblies are, I'm certain that this smaller brush was issued to help by doing a bit of scrubbing of the cantilever.
I'll bet that Dre_J (a long-time Lyra user) or Jonathan himself can clarify.
One thing is certain - using a longer, more flexible brush can do no harm. It might not clean as well however.
Of course, if you really feel aggressive, then the Mr. Clean Magic Eraser is for you, but based on your stated concerns, I don't think this is the case.
There's always reading glasses ...
Thom @ Galibier