Along with what has already been said, for the same package deal they offer an email, a vpn, a password manager, drive, and alot more space than the competition (500gig).

they include services such as proton sentinel.

https://proton.me/blog/sentinel-high-security-program

and secure core

https://protonvpn.com/support/secure-core-vpn/

one of the few still allowing port forwarding

https://protonvpn.com/support/port-forwarding/

how to use them in high risk countries

https://protonvpn.com/blog/vpn-servers-high-risk-countries/

development over the years and their dedication to bringing privacy, security, freedom of information to the masses speaks for itself.

Encrypt the planet