This is an encryption key seed, not a password. Save it somewhere secure so you don't lose it. No one can recover it for you.
Unless you trust me and trust AWS, this is the only thing protecting the data you enter here from being publicly avaliable.
If you are super paranoid, it needs to be so long that even a supercomputer can't guess it.
(about 128 bits of entropy, the generate button gives you that)
If you trust me and you trust AWS, or you don't think anyone will be dusting off the ol' GPU farm to crack your passwords, then something like four words is probably fine.
SEQUENTIAL READ PASSWORD MANAGER IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND.
For more information see the LICENSE file on GitHub.
If you want to rely on this application in the long term I advise you to host it yourself with your own AWS account.