Back in the days when there were less maps we played every map back to back
Ooh a little higher, now a bit to the left, a little more, a little more, just a bit more. Oooh yes, that's the spot!
Seems odd. You would think they would not want to produce a card that isn't used, just on a cost issue.
Cost of a normal 54 card deck (i.e. 4 * 13 card suits + 2 jokers), not much.
Cost of a special deck with just the 52 cards you want and to exclude the jokers would be higher.
Thus it is cheaper for them to give you the extra two cards (or in your case 3 jokers per deck, but I digress).
The executive summary:
Cost of two normal decks [b]