You most certainly can maintain/create a crown on a driveway with a box scraper by dropping one side of the box lower than the other. It requires you to ride the 3 point lever to maintain a grade, but it is possible.
Mid to high end rear blades also have the ability to tilt the moldboard to accomplish the same thing.
That being said... I have all three. If I could only have 1, it would be a box scraper.
ETA: You don't need to shift a grader scraper (land plane) side to side... The cutting edges are already positioned to move material from right to left from the vantage point of sitting in the seat facing forward. Its not a massive amount of angle, but it does work.