I'll admit I don't know enough about entropy. But is that analogy accurate?
Electrum generates a random phrase, the grid generates a random grid, then I put a random shape with my seed words somewhere.
Anyway, you're probably right.
I like the idea of BW, but it needs to be better for using an already generated seed to keep TX off chain. Its not so intuitive to me.
I might try it with an overlay, like a piece of paper with holes that sits on top of the grid and points out its order. Storage of course would need to be kept separately to the grid.