Earlier quoted context omitted.
Writing jQuery to accomplish a feature like hiding one element if another is checked is significantly more code and more error-prone (not to mention difficult to test) than doing the equivalent thing with a tool like Angular is.
It's 1 line with jQuery, so I guess "significantly more" is relative?
EDIT: as for your original question ("significant amount of FE functionality"), from my experience jQuery loses a lot of its appeal when you have over 1k lines of JS, and I guess over 5k JS frameworks (React, Ng, Ember, Vue) start to be significantly better. When over 10k jQuery would be crazy mess (I have seen one such project, it was fun trainwreck).