Knowing the build was reproducible tells me nothing of value.
Knowing the timestamp of when it was built, or the source was downloaded tells me roughly how old the package is, which can be useful for a variety of reasons.
Knowing the timestamp of when it was built, or the source was downloaded tells me roughly how old the package is, which can be useful for a variety of reasons.
It does. It proves that the given package was produced by the given source code. However, you can keep the timestamp as well! One of the goals of reproducible builds is to record values like this so it can be replayed later at a future point in time. This is done by the BUILDINFO format.
Would you rather you get a timestamp embedded that tells you it was built today, or take the hash and be able to find the exact revision.