Edit: And I'm sure I've put more weight on that one phrase than almost anyone else, but I've worked at startups for years now and been through rounds of layoffs at a couple. It's appropriate to err in the other direction.
Insistence on a long formal letter seems sort of like an east-coast style insistence on wearing a suit; it isn't really "for" anyone. If it makes the wearer/writer feel better about what they are doing then go for it... otherwise who is the party that cares? Pincus is a scumbag but I don't think this is an example of why.