You’re right that a marginal note can be a quick shortcut, but it’s a gamble on the reader’s later context. Rewriting the paragraph doubles the time spent, yet it forces you to process the material more deeply and creates a clearer mental map that you can reuse. If I ran a quick test, I’d note a glyph for a whole paragraph in about a minute, then later try to explain that paragraph from memory. I’d then rewrite the same paragraph over five minutes and see how much easier it is to recall and connect it to other ideas. The time saved with a glyph is real, but the retention drops noticeably unless you’re prepared to fill in the gaps later. So the choice depends on how much you value speed versus long‑term clarity.