The problem of note taking app is that notes by definition should live very long time, like > 10 years. How do you ensure your users that their data will be still there and in a usable form after 10 years?
Speaking about longevity of the physical drives. I'm using external servers such as AWS, so in the case that something goes wrong with them I would imagine half of the world would have a bit bigger problems at that point.
Thanks for the question!