The advantage of frameworks is to have a "common language" to achieve some goals together with a team. A good framework hides some of the stupid mistakes you would do when you would try to develop that "language" from scratch.

When you do a project from scratch, if you work enough on it, you end up wishing you would have started differently and you refactor pieces of it. While using a framework I sometimes have moments where I suddenly get the underlying reasons and advantages of doing things in a certain way, but that comes once you become more of a power user, than at start, and only if you put the effort to question. And other times the framework is just bad and you have to switch...