I think it goes both ways. Makes some things a lot easier and others a lot harder. Django's admin for example, can often give you 90% of what you are looking for with very little effort. It doesn't take a lot of effort to learn it. The again, if your application falls outside that model, no point in trying to shoehorn it in.

I would also say that frameworks keep things consistent(I know Django well, so based on that). I recently added Django-rest-framework to my application. It took very little to learn that as they have tried to keep the coding style the same as the class based views. Using them is almost the same, so after the initial half day or so in the docs, everything just clicked into place.