&gt; I don&#x27;t think your comment really engages with my point. I never mentioned Erlang or functional programming [...]<p>Sorry. It was mainly a response to &quot;JSON and XML are only &#x27;wasteful&#x27; if you don&#x27;t count developer time. Once you do, it suddenly makes a lot of sense to &quot;waste&quot; hardware resources. After all, programmers are expensive. Hardware is cheap.&quot;<p>And pointing out that it really depends on what languages or type or programmers you use and what &quot;hardware&quot; is. In some languages binary parsing is really easy and just as cheap and elegant as using a json parser. And well, Joe is Erlang&#x27;s father, so point out Erlang was obvious choice.<p>As for hardware, bandwidth is not hardware. It really is &quot;something else&quot; -- a shared resource usually. And if there are enough devices using this even small changes start to make a difference.<p>Think a bit like a nested loop -- a small optimization in the inner loop might have large visible benefits. Or say, a huge database with 10B records, choosing an 32bit int vs an 16bit one for a column will make a for a good difference in size. That is basically where Joe was coming from. Really valuing bandiwidth as a shared resource. (He also likes to talk about protocols as well quite a bit).<p>&gt; Again, the vast majority of mobile data isn&#x27;t JSON or XML<p>The important data is JSON though, the control message, the pages that load (and they are slow), stuff that stops, start, manages everything all that is JSON.<p>&gt;  If mobile bandwidth was a Californian drought, video would be alfalfa farming<p>Hmm, video is  50% of all traffic on smart phones. (<a href="http:&#x2F;&#x2F;www.ericsson.com&#x2F;res&#x2F;docs&#x2F;2015&#x2F;ericsson-mobility-report-june-2015.pdf" rel="nofollow">http:&#x2F;&#x2F;www.ericsson.com&#x2F;res&#x2F;docs&#x2F;2015&#x2F;ericsson-mobility-repo...</a> says 45% in 2014). Not that the rest is all JSON but, I wouldn&#x27;t say it is all just &quot;taking showers&quot; type of equivalency, it is more like grapes, almonds, strawberries, and walnuts.