Multi-camera editing and synchronizing
 

I've watched a bunch of Premiere Pro training from different instructors, and in the chapter on multi-camera editing, they always show the step of using the "Synchronize" option before nesting the sequence into another and enabling multi-cam. My question is... why? What does it do?

I've always just lined up my clips, making sure they are sync'ed manually, but afterwards I've never used clip markers or chosen "Synchronize" so what is it for exactly? Why the clip markers? Is it if you have consistent timecode across all angles?

This could be an obvious question, but I've never needed to use it.