If you're going to condescend to a stranger, be right. A commit conceptually has a tree of complete blobs that git will diff as needed. git has options that make it more or less sensitive to differences even between unrelated files, so it ignores any delta encoding that may or may not be used in packfiles (and never in loose objects).
If you're making an efficiency argument, git doesn't really try to beat the rsync algorithm even if you ignore the metadata. If you're making a "some people know git and nothing else" argument, fix the team, because that's a serious deficiency.
> A commit conceptually has a tree of complete blobs that git will diff as needed
You're a bit confused about the difference between "concept" and "implementation". There's multiple ways to conceptualize git, but the one I offered is the one presented by the default porcelain while the one you offered is closer to the implementation. The encoding used for storage is entirely irrelevant to my point.
Anyways, my point had nothing to do with efficiency but was related to the topic at hand; that is, whether it it safe to use git to put code on test machines, and indeed whether that's safer than the alternatives. Nothing you said really addresses that point.
If you're making an efficiency argument, git doesn't really try to beat the rsync algorithm even if you ignore the metadata. If you're making a "some people know git and nothing else" argument, fix the team, because that's a serious deficiency.