»But in todays CPUs there is no advantage using the short thing. You can add 64 bits or 8 bits, takes the same amount of time. And you look up what is the cash value of having saved seven bytes on a number. When you add that up it is zero. So there is no benefit.« [1]
As long as you are concerned with adding a bit of eye candy and interactivity to a web page this may be true enough to get away with the JavaScript way of making every number a double precision floating point number but there a other domains where this will not fly. And even in the world of JavaScript asm.js is trying hard to overcome this limitation.
He is comparing Java and JavaScript and implies that it is a bad choice of Java to offer several options. And given the broad range of applications Java is used for I don't think this is a justifiable opinion.
As long as you are concerned with adding a bit of eye candy and interactivity to a web page this may be true enough to get away with the JavaScript way of making every number a double precision floating point number but there a other domains where this will not fly. And even in the world of JavaScript asm.js is trying hard to overcome this limitation.
[1] http://www.youtube.com/watch?v=bo36MrBfTk4&t=42m17s