Steam already has account verification. There isn't really a need to have a second account to play a game.
But that only verifies your steam account, it doesn't do anything to verify your Elite Dangerous game account. If someone hacks your steam account they can just steal all your steam only stuff, delete whatever they want, cancel games etc, but they can't delete your ED account which is hosted by FDEV on thier server because they are two separate companies, Steam only sells ED under licence and FDEV are duty bound to protect the game accounts registered with them regardless of what protocols Steam uses. Yes FDEV could stop doing that, and when someone hacks into your FDEV account and changes your FDEV account password you will no longer have access to download updates and expansions, that's because Steam and FDEV are two different companies!