What a "framework" that isn't your app gives you is the ability to have a common language to describe and build your app's framework/DSL.
The larger the team, the more important a framework becomes. The smaller the team, the easier it is to have "less framework" that you aren't totally defining yourself.
That said, the real benefit in most frameworks is the solved problems. They might not solve them in the most optimal way, but is reinventing the wheel adding the most value in most cases? Nah, probably not.
Then again, sometimes reinventing the wheel is fun.
What a "framework" that isn't your app gives you is the ability to have a common language to describe and build your app's framework/DSL.
The larger the team, the more important a framework becomes. The smaller the team, the easier it is to have "less framework" that you aren't totally defining yourself.
That said, the real benefit in most frameworks is the solved problems. They might not solve them in the most optimal way, but is reinventing the wheel adding the most value in most cases? Nah, probably not.
Then again, sometimes reinventing the wheel is fun.