> Caring about some metadata changing does not seem to be as useful from a security perspective.

If the metadata were neatly separated from the executable portions of an artifact then it indeed wouldn't be too much of an issue[1], but it often isn't. It sometimes gets embedded into strings and other places in the executable itself where it theoretically could have an impact on the runtime (and of course makes executable signatures unreliable, etc.). Without that separation comparing two potentially-the-same executables becomes equivalent to the Halting Problem.

[1] You could sign only portions of the executable, for example... but such signature schemes are brittle and error-prone in practice, so best avoided. So you'd ideally want any and all metadata totally separate from the executable.