Sp1itLip I could be wrong, @Justin can correct me, but I don't believe the backups are included in a packaged game thats exported, just the active .scns.
The .backups are kept (up to 2 at a time), not just in case of accidental deletion, but also in case a model somehow gets corrupted (which can be quite a common occurrence so they are vital to hold onto really, until a game is finished and exported, just in case).
Better to have them, not need them...then realise you suddenly need them...and they aren't there due to overconfident purge.
A couple of kbs is a small price to pay for not losing a model I would say.
Unless it's a deleted model you arent using at all anymore, then it's safe to also remove the .backups too.