If you keep the book secure, it’s probably safer than any computer based record system - right up until someone untrustworthy gets their eyes on the book.

With a physical book, you can store it in a safe deposit box when you don’t need access, make partial copies, copies take (everyone, bad guys and good) significantly longer to make even with a photocopy process… most importantly, people intuitively understand the vulnerabilities of a physical book.

Now, the physical book won’t stop keyloggers…