Having shot sports, and even for informal portraits, I've found it useful to hit bursts, especially when my old EOS A2 gave me 5 fps easy. But on a capable camera that's just one of the tools to use, not a way to avoid thinking about your shot and just blasting away. So, obviously there are scenarios, depending on the photographer and subject where it's perfectly the right thing to do. I have found that 3 fps and slower cameras leave me missing more shots than just anticipating, and nailing the shot, mainly in fast paced action. So no technique is perfect by itself. Practice is the key, IMHO. Know your camera, and what it can do by pushing its performance boundaries. Experiment, know your limitations, and maximize your chances to make a great shot. Just my $0.02..