I investigated the flavor question by heating 15 oils — 4 olive and 11 seed oils — with nothing else in the pan, so I could taste what heat alone does to them. And I served some of them to trained oil judges.
We were surprised at how thoroughly heat obliterated the flavors in cooking oil until they all tasted more or less the same. Even prize-winning, and costly, extra-virgin olive oils lost much of what makes them special, though they retain their apparently healthful pungency. To get food with the green and fruity flavor of good olive oil, it seems more economical and effective to fry with an inexpensive refined oil and drizzle on a little fresh olive oil after cooking.