It is a little more mixed than that. Granite is generally cheaper and has better heat resistance. Granite is porous, so it stains and needs sealing every year or two. Quartz/artificial takes less maintenance, is a little stronger, so it is more scratch resistant.
Granite is porous and polished granite is porous. It has to be sealed to prevent absorption and staining. It has to be resealed periodically (annually or semi-annually) to maintain the protection.