In short, Fetch API- it's a new Promise- based standard for doing AJAX requests. Syntax for XHR was provided more then 10 years ago (XMLHttpRequest2 - about 4 years ago). Many things changed, we got HTML5, CSS3, also close to start using EcmaScript 6. From jQuery Deferred, $q and Native JavaScript Promises people became familiar and like promises in JS. It’s time for new laconic API to do AJAX-req
