Congratulations for having the patience to write out long strings of characters on paper and type them out repeatedly, but that doesn't sound very safe.
You can make it safe by using a secret key in conjunction with the keys. For example; all passwords as written but the third character must be # instead of what's written. This renders the book useless if stolen or copied.
If you keep the book in a locked draw and use some tell tails to ensure that you will know if it's been opened you have a strong chance of being able to know if you have been physically compromised.
Any online key store is vulnerable in a number of ways, end to end security is hard. The biggest issue is that your provider might be placed under significant physical pressure relieved only when your account is compromised.
Well "safe". Once your written down password is compromised (e.g. with a photo of a page), the entropy for cracking the password is tremendously minimized. In combination with dumped hashes of the site in question even more.
