They are very good at letting you make the quick easy change while providing no helping hand in ensuring all your code is utilizing the data structure's new sch

They are very good at letting you make the quick easy change while providing no helping hand in ensuring all your code is utilizing the data structure's new schema correctly They are "easy" in that sense which makes them popular with a subset if developers, while another subset loathes the terrible language services/tooling. Incidentally many dynamic languages seem to have attempted to bolt on some faux type system; python type annotations, phpdoc, jsdoc, type specs, etc, etc.