Andrew, Andrew, Andrew. You are brilliant. Your post made me understand why magic works the way it does in the cosmere. I think I've figured it out.
(Of course, my theory implies that magic users are most emphatically not Splinters)
It is way, way too late for me to explain, or comment on your stuff. Though, I will say that the fact that if Snapping involves overcoming a piece of Ruin, then that means ingesting lerasium does not require such Snapping. One of your mysteries is solved, Andrew.
Good catch, Andrea. I had forgotten about that fact about overcoming a piece of Ruin. Bad me.