Can you argue a bit more genuinely and not pick on such a minor point as validation? I think parent mentioned other points? How about the logical shift to let client do client things, and server do server things? Server concatting html strings for bilions of users over and over again seems pretty stupid.
Why not stress the argument further and say server "concats" http strings or sql strings? It's because of the nonsense from the web platform that inefficient text-based transports such as json became prevalent in the back-end btw.
