Changes on the client still usually roundtrip to the server to get the data (via a Rest call these days, then parse the JSON response, then render and apply the

Changes on the client still usually roundtrip to the server to get the data (via a Rest call these days, then parse the JSON response, then render and apply the diffs to the DOM). And I don't buy the argument that javascript-based client apps scale better than servers rendered partials where there's been over a decade worth of solutions for scaling out the server layer. Also, you'd be applying a lot of the same techniques for scaling a pure API as something spitting out partial web views.