Why is the Bantu migration the most important migration in history

The Bantu migration was a migration between 1000 BCE and 500 CE, and is believed to be due to a development of agriculture and the use of iron, allowing humans to now also live in other areas as they didn't depend on hunting / foraging alone anymore. In human history, it's believed to have been the largest migration, and probably shaped our evolution as humans in a very important way.