Before ES6 im curious did you always need blocked scoped variables? Of course we used iife's when we needed to but how often did we need to do that compared to the times we used regular variables. Is it always worth the extra overhead to enforce everything being blocked scoped? What about times that we needed to alter something outside the scope? whether or not thats always a good idea is another discussion but there are valid uses. I remember people were getting all worked up over functional expressions vs declarations saying expressions were 'the one true way' since it more closely resemebles how the compiler reads it. As babel shows let and const are just var's with extra overhead. Dont get me wrong let and const are in the right direction but they are not 'the one true way'