Requiring a google email address and chrome for a secure messaging system? Very strange move.
Make sense since that's how you sign into the Chrome app store to download the app.
Go get bower and npm and build it yourself. It'll be a zipfile.
I don't think it makes any sense at all.
Even if you do use gmail/google in some places (I don't) it's not a given that you want to tie that identity to this app or these activities.
A throwaway google account is getting very difficult since google automatically flags an account with no mobile phone number attached to it as a "suspicious activity" account, immediately forcing you to add a mobile number.
Google is not the Internet. Their app store is not the Internet. I can't believe that the people I know to be behind this project have tied it to google in such a necessary and intimate way.