While astromech droids don't usually serve drinks, R2 did serve drinks on Jabba's sail barge. Someone must have liked the idea because this droid is an R2-D2 Moving Fridge with the ability to carry drinks within his compartment.And yes, he can move on his own.
"Excuse me sir, but that R2-D2 is in prime condition, a real bargain." - C3PO
