Thankyouverymuch. I am gonna keep using my password book.

There is no sure way, as a private person and not being expert in security, to secure your browser. But there are ways to limit the damage that can be made. Maybe just don't make it too convenient and have a database of all your passwords on all your devices?

Not only that, I would argue that a physical booklet is not only more secure but also safer. Nothing short of a house fire will destroy the booklet, and however much I like to rave about old-school ThinkPad durability, I don't think my locally stored encrypted database would survive that either.

the modern security hazard is not someone reading your post-it that is sitting on your desk, it is someone remotely getting access to some part of your computer or some service you own that can tell you what the password is.

The post-it note in our world is more secure than lots of things that have replaced it.

on edit: I see Mordisquitos said it better than I.

Is it? If someone is physically in your home you are in greater trouble anyways and even then they likely aren't going to be grabbing a notebook. Just keep it somewhere nearby but hidden (notebook in a drawer on the desk).