As a business, even as a "project" the needs change between the start and the end of a project. Periods of low and high activity coincide with the various phases of things. Expecting some crunch time at the end and allowing some slack time at the start/middle allows a natural flow.
Now managers have decided employees must work at a high level of output/at crunch time pace ALL the time. Any change in forecasted points, burn down results in meltdowns at the VP and higher levels, while actual expectations, requirements and deadlines are changed at the drop of a hat multiple times.
Waterfall (not the sprint version of waterfall, the Deming version of waterfall with iteration between steps) gives a much more natural alignment of this while also ensuring the starting point doesn't get shifted at the whims of a VP with a "good idea" in the middle of a project.