One major advance that’s overlooked in handwriting your manuscript first. Is that it can serve as proof the idea was originally yours.
I know this isn’t traditional the propriety of the copyright agenda but it’s better than having no proof at all.
Let’s say for instance. You wrote a phrase ten to twenty years ago and decide to publish it. But someone else later worded something very similar and then accused you of copyright infringe. You can always pull out your old notebooks and prove you wrote it prior to their publication and accusation.
If the accuser want to go scientific about it. The ink can be easily tested to prove that the date’s ink match the age of the manuscripts ink or pencil carbon. I wouldn’t recommend using a pencil it fades too fast.
I recommend formal writing. Not the popular block printing. Block printing is too easily copied. Cursive writing is hard to copy.
I know most authors won’t encounter this but you never know where your work might land.
LOL! Now, the down side is transferring it all to a computer or typewriter. But the benefits are worth the trouble.
Courts are still into the paper. They don’t trust the computer. Too many unscrupulous smartalecks know how to alter the date on a file.