It's not just the money...
Yes, this will cost the freighter boys some extra money, and they will probably be pissed off about that, but I think the biggest challenge will be organizing their DXB 'layovers' now.
The whole idea of starting a dedicated freighter operation is to minimize the disruption caused by the freighter ops to the pax side of the operation. Indeed, the freighter guys can expect lots of roster changes, either in DXB or downroute.
Now, suppose you come back earlier then rostered in DXB: do you still need to find a hotel the moment you get off the airplane? Good luck with that during e.g. Gitex or Cityscape conventions, or when the Tennis is ongoing around the airport etc...
Or, you have everything arranged like a good boy, but now you pick up an extra leg downroute and you won't be in DXB when planned: do you really think the hotels are going to reimburse you?
What about explaining to crew transport before every flight where they have to pick you up this time...
So yes, the loss of money sucks, but I think the biggest stress factor will come from trying to arrange a bed every time you are in DXB, unless you settle for a small one bedroom in a cheap area. That will probably cost you about the same...
Good luck to the freighter boys, seems to me they'll need some.
MR8