While I tend to prefer deeper water fishing, pitching to heavy cover is a proven technique for all seasons. When the fish are related to beds, being able to put your bait where you want is absolutely essential. When those beds are up in the woods great pitching skills can make all the difference. I fish with a guy who like JT above, pitches to impossible spots with rifle like accuracy. He catches fish that I simply can't. I am working hard to improve my skills because my fragile ego can only take so many whoppings . So, in summary, pitching well is an important skill any time bass are holding in heavy cover, which is pretty much anytime!
I can't really say much about flipping. I don't much like it either.