[saghm]

There are some subtle differences in whether the canonical representation is a snapshot of the current state of the repo or a patch applied to the current state. One simple example is reordering; assuming your modifications don't change the same line, reordering patches arbitrarily won't change the final result. If you instead store snapshots of the state at each point, then reordering the snapshots won't necessarily result in the same final state, since you might have moved a different state to the final position.

You're correct that the two models are equivalent, but version control is about operations that you perform on the models, and those operations will not be the same for both models. You can reason about your git history as if its a series of patches, but git itself doesn't know how to deal with any model other than snapshots.

[jameshart]

Given that git commits are immutable, reordering doesn’t matter. Any history rewriting involves creating new commits - whether those are new snapshots or new diffs.