Because the plan serves everyone except the person updating it. It exists for the client report and the status meeting, so it is updated the night before both and is wrong the rest of the time.
Meanwhile the team works from a task list nobody outside can see, and the two describe different projects.
The plan is the tasks. Updating a task updates the Gantt, the client portal, capacity and margin, because there is nothing sitting between them.
So maintaining it is not reporting overhead — it is how the client finds out, how billing happens and how next week gets staffed.
It will not level resources for you. It shows who is over capacity and by how much; deciding what to drop involves people and commitments a number cannot see.
It also will not estimate work nobody has scoped.
Status meetings shorten to the part that needs a conversation, because the synchronising half already happened.
Overcommitment shows before the week it lands, and a slipped dependency moves the delivery date immediately rather than at the next review.
No. Sprints are available; continuous flow works equally well.
Only the phases and deliverables you expose.
Time logs against tasks, which is what makes billing and margin work.
Half an hour on your own numbers is usually enough to say whether Loop is the right place to start.