The minor advantage of having time stamps in the text Minor? How else can we have an accurate version number? Doing it by hand, or doing anything related to particular vc systems, proved completely untenable for these widespread files. That's the whole reason we introduced the timestamps in the first place, as you know.
it would make sense to remove the Local Variables sections from the copies installed via gnulib, I guess, as a compromise to avoid the "attack vector" (vastly overstated, seems to me). since changes to the copies should not update those time stamps. In principle, I am doubtful. If someone (mistakenly or on purpose) edits a downstream config.guess or whatever, it seems like a good thing to me for the timestamp to change, so it won't be confused with the upstream original. k