Could you expound on what the use of asymmetric crypto if not for authentication? https actually uses symmetric encryption for content and public/private for au

Could you expound on what the use of asymmetric crypto if not for authentication? https actually uses symmetric encryption for content and public/private for authentication, iirc. I don't think undersea fiber lines alone would stop a nation state like the US from intercepting them. Undersea fibers need maintenance and repairs done on them, and I imagine putting in a prism to splice off a connection during a maintenance window is within most nation state's capabilities. I don't think the exact numbers are all that important, just that it's non-negligible. When the implementation and maintenance costs become negligible, turning it on by default makes sense. Until then, opt-in makes sense. Authentication is the toughest part that I don't think is yet solved in a mass deployable way.