If I adhere to 3 lives 1 continue, my approach to a game is far more engaged. There are aspects of the gameplay that I might skip knowing I can just hit continue. With credit feeding, tense moments become infrequent, and each button press seems like a means to "make the screen go forward" as opposed to your character interacting with the elements on the stage panel you are currently at.
There are times when I eventually just want to see the whole game, but more often than not I try to restrict myself to limited lives/credits. A 1CC would be a side effect of that, but the main goal for me is to keep the gameplay rewarding and engaging by making the encounters with enemies and obstacles meaningful.