But that is exactly the point. It is inconvenient, so when you choose to do it, it implies you care more about that conversation.

It doesn't mean e-mail isn't perfectly fine for a lot of conversation, but you should expect people to treat it accordingly: You care enough to write an e-mail instead of an IM, but not enough to call them or a arrange a face to face.

Sometimes it's perfectly appropriate to convey that. Sometimes it's not.

You still have keyboard.