Nice idea, but to be honest it doesn't have any major benefits. You can put the team in tanking mode and be ok for the next time you come (1 or 2 month). The problem here is that the time consuming elements here are farming packs, renewing offers and contracts and of course the daily gifts. This is why a vacation mode doesn't give you any real advantage, you have to be present for these things otherwise it is the same as tanking.