The short in question was external to the pack, and thus would have blown the fuse. If you short the pack internally an external fuse won't be in the load path.
Fusing mid pack is sometimes done on larger packs, 48V would be low, but not unheard of for this practice. Generally speaking properly protecting the terminals is a better approach than adding fuses at random. Fusing won't protect against shorting both terminals of the same cell.
Using properly insulated tools is also important when working on a pack. Random fuses aren't a solution to that problem either.