When the Pardey's say the genoa
is not a cruising sail I think they are refering to the fact that, in the trades, many boats would be over-powered with a genny. But, there are a few boats that are not over-powered with a genny and the smaller boats with 3/4 rigs won't balance without one. Perry, for one, designed a few boat for the Seattle
scene with fin keels and short rigs that can handle a genny in a stiff breeze. As with any sail choice, it depends on your boat.
Having said that, the genny is probably a bit over used and the Pardey
statement should be taken as an admonission to power your boat appropriately for the conditions.