Charlie is a slow player for sure, but so are a lot of other champions, like Jeremy Jones, Danny Basavich, Dick Lane, et cetera. When it comes to tournament play, I believe a player should do whatever makes them comfortable to win.
The funny thing about Danny Basavich is that I've seen him play on the shot clock, and he plays just as good playing fast as when he plays slow.
JAM, that is exactly the reason most people dislike slow play so much. As you said, the majority of these guys play just as well at a reasonable pace. Playing that slowly is a way of making the opponent comatose while the guy takes 20 minutes to run 5 fairly easy shots. The entire time the opponent is becoming more frustrated and distracted. It is amazing that these players can focus this long while shooting such simple shots. It is basically impossible for the player in the chair to retain intense focus while doing sitting for this long.
I am not saying that it is cheating or even that it is not a smart move - because it is. I am just saying that no one except the player appreciates it. I can almost guarantee that despite the fact that both Charlie and Danny have extreme focus, if they were to play each other and play their usual rhythm they might both falter mentally or the match go well beyond the allowed time for a couple rounds of the tournament.