the use of rebasing is simple: You have contributors and one committer. The committer is also a developer whose branch can have changes anytime. The contributor

the use of rebasing is simple: You have contributors and one committer. The committer is also a developer whose branch can have changes anytime. The contributors must rebase on committer's main branch so that the committer can do a fast forward, clean merge when the time to merge comes. Clean upstream merge is important, since you have multiple committer's who are contributors to a bigger branch. The hierarchy goes on and on until the top (e.g. linus torvalds). So rebases are a way of achieving clean upstream merges, and it becomes more important when you have many levels of hierarchy.