I do actually use a password manager (zx2c4's pass) to manage my own passwords. But my mother has a book I purchased for her as an Xmas gift one year, for exactly the reason you described, I am confident she understands the security properties of a book, (e.g. a stranger left alone in a room with the book can read it) whereas I have my doubts with a password manager.

I used a book for passwords issued by that employer because at that time they lacked any in-house password manager and I foresaw from the outset that I would want to be able to hand them "my passwords" in the limited context of that employment as distinct from stuff like my personal Wikipedia account, my Google account and so on.