Ellis for McElhinney? A good deal?

Ok so as a Tampa Bay Fan, when I read "Bolts and Ducks Swap Goalies" my first thought was Ellis for Hiller? Hardly! Then I saw it was McElhinney (who is a good goalie) for Ellis?? Smith maybe, but why when Ellis is in good form? Ok making Cap Space is probably why the deal was done, but surely they could have got an established goalie for Ellis?