I'm surprised he didn't mention editing. On a computer this is trivial; on paper you need an ink eradicator, correction tape, or correction fluid. And even those are only good for small corrections. If you want to insert a sentence or paragraph somewhere, that's not really possible with paper.

Also, if you want your text to be published online or printed, it needs to be digitized somehow. Which is a good OCR tool for handwriting, especially if it's not very legible? Just feed scans into Gemini perhaps?