Should I write a description?

Yes, and it is worth two minutes. The description is what somebody reads to decide whether to open your note, and it is the text a search engine matches against a student's question.

Aim for thirty to eighty words — roughly two hundred to five hundred characters. Below thirty a reader cannot tell whether your note covers what they came for. Eighty is the sweet spot, and past that it stops making much difference.

List the topics covered, the chapters, or the syllabus points, one per line. A note whose description lists its contents gets found by people searching for any one of them.

Only the first hundred and fifty-five characters or so appear underneath your title in Google — but all of it is what decides whether your note is shown there at all.