I was considering signing up and just noticed this on their site... Definitely odd. I understand they want to be easy to use and feel seamless, but it defeats the purpose of the password protected private key.

https://www.backblaze.com/backup-encryption.html

To decrypt your data, you are required to enter your passphrase on our secure website. When you do so, it is passed over an encrypted connection to our datacenter where it is used to decrypt your private key, which in turn is used to decrypt your data. Your passphrase is never saved on disk and it is discarded once it is used. As before, once we decrypt your data on our secure restore servers we then zip it and send it over an encrypted SSL connection to your computer. Once it arrives on your computer, you can unzip it and you have your data back.