Eh, I would say creating one (or something similar) is a useful exercise to help break up large tasks and think more thoroughly about how to split work within a team. It also helps to highlight possible bottlenecks and is a useful visualization so everyone on the team is on the same page.

Agreed. I love gantt charts because they show where things have to come together. I rarely give time estimates when asked but I always ask when something is needed from me to not hold up other people.

Wouldn't that just be a dependency graph?

Yes, and drawing a dependency graph would be a useful exercise too, but I rarely see managers drawing either a gantt chart or a dependency graph.

What is the difference between a Gantt chart and a dependency graph?

Gantt charts typically have resource assignments and time estimates. Dependency graphs just say Bravo requires Alpha to be completed first (for example).

Dependency graphs can also be annotated with the resources required for each node or edge. Resources are estimated by summation, time is estimated by finding the critical path.

Gantt charts are a partial linearization of a dependency graph. People tend to fixate over the dates shown, allow schedule pressure to "correct" previous estimates, etc.

According to some early users of Gantt charts, they are a great tool for summarizing a plan, a terrible tool for developing and maintaining one.

I think problem is not creating gantt chart but impression of knowing exactly how complex projects will unfold. If you do this without creating gannt or any other chart you end up with the same result.