Over the past few years JSON has become the standard of data interchange formats. Before JSON, XML was king. XML was great at modeling complex data but it is difficult to parse and is very verbose. JSON really took off when rich AJAX driven sites were introduced as it’s very lightweight. It is in a human readable format, quick to parse and its simple key/value representation cuts out all the verbosity of XML.
As a consultant I have the opportunity to look into other peoples work. I'm hired to do technical scans, write the technical demands on new projects and keep an eye on it if they are taken into account. In these reviews I notice a lot that Extbase is (ab)used for everything. And I mean for everything.