Obviously they made the R2-D2 luggage a carry-on because as a checked bag it would immediately be stolen by some bag handler or TSA fanboy. I mean that's what I would do anyway. Since I'm generally a swell guy I wouldn't steal the stuff inside though. It could all go on the claim conveyor belt in a garbage bag with a note on the outside saying, "R2-D2 Suitcase Contents. Sorry dude. You tempted fate and lost."
In size, the Artoo carry-on is not screen accurate by at least 15" in height alone, but it's hard-shell case should make it past security and fit in your overhead bin so I guess the scale issue is forgivable. Complete measurements, including 360 swivel wheels and telescoping handle, are 14" x 22-1/2" x 8-1/2". R2-D2 interiors are fully-lined with a divider, integrated pocket, and elastic straps. Empty weight is 5-1/2 pounds.