Is student assessment for accountability purposes educationally beneficial?

What do students and teacher learn from large-scale assessments that are given for accountability purposes? Do teachers find out what specific learning difficulties their students are having? Do students learn where they stand in relation to a curricular target or goal? In general, I'd say the answers to these three questions are: not much, no, and no. These thoughts come to mind as I've been reviewing some physics questions intended for use as preparation for some of these large-scale assessments. 

Unfortunately, the target or goal of a large-scale assessment often seems to be a cut point score or a designation of "proficient." Even though "disaggregation of the data" is often performed by teachers and schools to see where their students need remediation, it seems as though the driving force for this is the "percent proficient" statistic, rather than students' reaching specific curricular goals. 

But it doesn't have to be this way. I believe classroom assessment practices that are developed, implemented, and carried out by the teacher have the potential to be used for accountability purposes. If teachers become "assessment professionals" and emphasize the importance and interdependence of curriculum, instruction ,and assessment in teaching and learning, then their own assessments could be used for accountability. We've seen a few examples of this in the research literature and work from Australia and the United Kingdom, but what would it take to implement this on a large scale in the United States? Nothing less than a cultural shift in our beliefs about assessment and accountability I suppose, not to mention ensuring that "highly qualified" teachers (forgive the use of a poorly operationalized term here) exist in all of our schools. 

What are your thoughts?