Correct when true. But if talking about all deadlines, you can sort them by category. One that I especially don’t like are populistic deadlines, when team burnout is used to: impress or brag before someone, get some quick results only to spend few weeks before even looking into it, set out of a thin air in a project of an RnD nature. Deadline is not only a planning instrument, it is also a force that allows to tick the box regardless of a true state. You cannot always expect them to be used in a sensible way, because other departments and heads suck as much as you do, or more, if they are further from physical/informational reality. Tight budget means tight planning, but it might also mean that your chiefs are simply underperforming.

Working on the edge of bankruptcy for years, never seen my “push hard this week (or: this sunday) it’s important to us” taken as important or used right away. I even learned to detect with high probability when the rush is based on cocaine and can be safely ignored.

This is not a rebuttal (I agree that deadlines are useful), it’s just the back side of this shiny coin of “effective management”.