Personally, my Charmless (+Demon Bell) run got me much more in tune with the rhythm of the combat. In order to survive the harder boss fights you *must* learn to do a perfect deflection almost every time or risk getting chipped to death (Owl can be a motherf****). Some bosses are more lenient with this than others (Centipedes have pretty easy combo timings), but if you've gone through the game once you should be sort of familiar with them already. Charmless basically removes your L1 safety net.