Systems thinking, or the study of system dynamics, offers a principle that helps explain why Lean-Agile has been so successful for our teams.
In systems thinking, there is the concept of feedback in a system. Controls in the system monitor the stock levels and take action to adjust the inflows or outflows. Delays in system feedback can cause oscillations in stock levels. A full discussion of systems thinking is outside the scope of this book, but for more information, consider Thinking in Systems, by Donella Meadows, 2008.
For Lean-Agile teams, the daily standup meeting reduces feedback delays to 24 hours. In a brief 15-minute meeting, each day, the Lean-Agile team can see the stock of work items on the Kanban board and adjust the flow of work items through the process steps as needed. In some organizations, there is only a monthly financial report on progress, increasing the delays. The delay can result in not having the project finish on time or it costing more than expected.
David Snowden’s discourses  on complexity science also help explain why the daily standup is needed because the development team is a complex adaptive system.
The Kanban board helps see the emerging patterns, and the daily standup lets the whole team see the situation, so they can offer ideas for a solution that could not have been envisioned before the situation happened. Our prior method of having the Lead maintain the project status in MS Project reduced visibility to only the Lead rather than the entire team.
Having weekly or monthly meetings adds significantly more delay 7X to 30X which leads to more issues. When people get worried about more meetings, assure them you will cut the meeting at 15 minutes and then follow through.