@thaodan I can only comment from perspective of CZ - here email-like solution (mojedatovaschranka.cz) is having specific features which common email cannot provide. Namely confirmation of login (enter), read receipt and confirmation of retention. Both are having legal consequences therefore cannot be provided as opt-in feature. Therefore while email is used for normal communication, legally-binding exchange (applications, extracts, submission) can only happen via DS.CZ service