E-mails have long been the gorilla of the communication world; they’re too big to ignore and they don’t always behave properly. Despite the frequency at which most people send emails, many are drab and often a mare's nest of ideas hurriedly typed with no real regard to the reader.
The result: If you are lucky to get a response, it could be off-base and completely impertinent to the topic at hand. Worse, you could receive a request asking you to re-explain everything. In this case, you're now re-doing work simply because you rushed through the first one.
If you send e-mails (and who doesn’t these days?) doesn’t it make sense to make them more effective? I'd say so.