But that doesn't make up for it for two reasons. First that is still not many. Even with a full day with 2 short rests that is a total of 6 times you can smite .... or less than once per battle. A 6th level Paladin can smite 7 times regardless of the number of short rests. Yes they are for less damage per smite, but not a lot less and not a lot considering the amount of overall resources spent to do it.
If you multiclass it is even a bigger deal. On a day with 3 short rests a Paladin 6/Hexblade 1 can smite 10 times since he can use all his slots for smiting. a Hexblade 6/Paladin 1 can only smite 6 times. If you go to fewer short rests that gap widens by quite a bit. In a short day without any short rests a Paladin 6/Hexblade 1 can smite 8 times, a Hexblade 6/Paladin 1 can only smite twice.