Partially I agree with you. This is to get rid of the hacks people do to work across organization wall.

Let me try to explain: A task is not just a text, it has context and history, and meta data. Unfortunately people use email for this which creates 100s of messages in a thread. Instead, if you keep single entity and keep updating it like you would do in any task management system, it will create better meta data and less headache to manage.