3. It's more secure than the standard encryption methods.
It absolutely isn't.
When compare with cryptographically strong algorithm(AES), it's easier to set/memorize the password(just 8-20 words) while keeping the difficulty to crack it.
If you desperately want to commit something to memory (although as I explain below that's a terrible back up method), then just memorize the seed phrase or use 8-20 words as an encryption key using a standard encryption algorithm, and not some homemade harebrained scheme.
The customized phrase is stored in your brain(that's very important.).
Here is why you should absolutely never rely on your memory for any critical information or back up:
Each year:
69 million traumatic brain injuries:
https://pubmed.ncbi.nlm.nih.gov/29701556/12 million strokes:
https://www.world-stroke.org/assets/downloads/WSO_Global_Stroke_Fact_Sheet.pdf10 million new diagnoses of dementia:
https://www.who.int/news-room/fact-sheets/detail/dementia5 million new diagnoses of epilepsy:
https://www.who.int/news-room/fact-sheets/detail/epilepsy2.5 million cases of meningitis:
https://www.path.org/articles/toward-world-without-meningitis/2 million new brain tumors:
https://academic.oup.com/noa/article/3/1/vdaa178/60433151.5 million cases of encephalitis:
https://www.sciencedirect.com/science/article/pii/S0163445322002110That's
each year, and that's only major conditions which directly affect the brain. Add in things like cardiac arrest, heart disease, sepsis, shock, diabetes, vascular injury, hemorrhage, poisoning, smoke inhalation, etc., all of which can cause secondary brain injury, and there are literally hundreds of millions of people every single year who suffer some form of insult to their brain which can lead to memory problems.
Do you want to trust all your coins to those odds? I know I don't.