[seabass-labrax]

I agree that most business communication is pretty low-quality. But after reading your post with the kind of needlessly fine-tooth comb that is invited by a thread about proper English, I'm wondering how it matters. You yourself made a few mistakes in your post, but not only does it scarcely matter, it would be rude of me to point it out in any other context (all the same, I hope you do not take offence in this case).

Correct grammar and spelling might be reassuring as a matter of professionalism: the business must be serious about its work if it goes to the effort of proofreading, surely? That is, it's a heuristic for legitimacy in the same way as expensive advertisements are, even if completely independent from the actual quality of the product. However, I'm not sure that 100% correct grammar is necessary from a transactional point of view; 90% correct is probably good enough for the vast majority of commerce.