The biggest benefit is more clear understanding of changes in development teams over significant periods of time. For example, when was this function changed?

The biggest benefit is more clear understanding of changes in development teams over significant periods of time. For example, when was this function changed? That's very hard to answer when the diffs are not semantic. The Eclipse IDE provides semantic diffs on top of version control when viewing specific commits (pending or already committed) but this is obviously not part of the underlying version control system and is limited.