The Prius V comes with 0w-20 oil. This should be a synthetic oil as, to the best of my knowledge, there are no regular/conventional 0w-20 oils.
While this may be the dealership spinning its own web on this, 0w-20 oil is specifically manufactured, and sometimes the dealership has the better deal than the other shops in some areas. BTW, in the Owner's Manual, Page 498, it says the following: