Most Excel Gantt charts are not really project schedules. They can display tasks and dates, but the scheduling logic usually remains manual. If one activity moves, someone has to update every dependent task, redraw the chart and check whether the critical path has changed.
Source: [Dev.to](https://dev.to/tmailletfr/i-built-a-dependency-driven-scheduling-engine-entirely-in-excelvba-4hbf)