When your team are working on that minimal viable product and finding product market fit story by story ticket by ticket things are small. Once systems get bigger and bigger and more distributed and cross domains how can QA and developers keep track of the overall quality without being overwhelmed by the small details?
Not that I have experience with this, but I'm thinking there needs to be a layered testing approach. Those consumed with the details and those consuming the system as a whole.
Both of these layers should work closely together so they can contribute to the pool of knowledge on either side.