Another week, another email newsletter. This time, the story is Punchbowl, a politics-centric newsletter founded by a crop of recent Politico alums including Jake Sherman, Anna Palmer and John Bresnahan. Ben Smith has the story, as does Maxwell Tani at the Daily Beast with some more juicy details. Why do we need another newsletter analyzing Beltway politics in a world of Politico Playbook, Axios, The Daily 202 and a hundred others? In fact, why do we need the voluminous output of tech-oriented newsletters covering startups (by my count, there are…