Game-changer... how? There are at least two players in email space that provide encrypted email and various auxiliary suites (Protonmail and Tuta), plus at least one well-trusted well-respected email service (Fastmail), and of course people can always self-host if they dare. What revolutionary they could possibly realistically bring in areas privacy and security to be an actual "game-changer"?

Not saying it cannot possibly be - just that I cannot think of any novel way how it would deserve a title like this in such a particularly tricky niche as email suite service.