The checksumming approach is still more flexible.

Example scenario:  a friend phones you for help with a software problem.  At some point while discussing the issue, you'd like to verify that s/he is actually using the same versions/files, because you can't replicate the problem on your side.  So, you create a checksums file of the installation tree and email it to your friend, who can then run the verification without needing any access to your machine whatsoever.