A public key is whats used to encrypt your data, when your sharing data within a team or workspace your public key is shared to other users within that team or workspace, this is so that when a user creates a shareable item (e.g. a connection, ssh snippet, etc) they will use your their public key, your public key and other team members public key to encrypt that data.
A private key is used to decrypt data that was encrypted by your public key, and only you have access to the private key. Your private key is also encoded with a passphrase and can only be decoded with the correct passphrase being used.
We use your account password as part of the passphrase to unlock your private key. If you forget your account password, your private key becomes unrecoverable, therefore leaving your account data to be permanently encrypted and locked.