If you don’t own Black Panther Pursuit or any of the sets that included Captain America, I guess it would a plus getting the both of them in this set but Super Heroes collectors tend to be completionists, so I think that scenario will be particularly rare. I guess you could always sell your spares on the secondary market, but really, who wants to do that?
Bag 4 finishes the fuselage and all that is left are the engines and tail section. You'll notice that this aircraft has a bathroom on board as well as some storage for a non-existent flight attendant. I think this is the first time that LEGO has put some additional details into aircraft besides just seats. Also there is only one pilot for a 2 seat cockpit in the set.
Parking capacity at Copenhagen Airport was greatly expanded in 2015 with the construction of a new lot as one of the first phases in an ambitious airport expansion plan scheduled to roll out in the coming decades. There are several lots: those near the terminals are very expensive, while the further-flung ones are cheaper (but have free shuttle bus service to the terminals).