Not at all! WhileSign is heavily integrated with Google and Gmail, you do not have to use Gmail to use Sign.
If you send your clients a signature request viaSign, they simply need to have a valid email address and internet connection. That's it!
Only our Sign for Gmail plugin and Google Drive and Docs integrations require a Gmail account, but you do not need to use those features to use Sign. Those are just added integrations for those using Gmail.