I agree that BB may not be as entertaining without Charley, certainly there will be less discussion generated about it.
But th problem with housemates like Charley is that she doesn't believe she'll be voted out, she thinks she's keeping it real and the public will love her. They clearly don't love her and one of the main problems is her arrogance.
With these types of housemates (Sezer was the same) part of the fun in evicting them is to see their face when their name is announced. To see that disappointment, to see that moment of realisation that people don't love her, to see her face when the boos are clearly audible through the BB doors!! I want to see that, I want to see her little deluded self-obsessed world come crashing down around her.
So yes, it may be better to keep her in for a while, but I will get great pleasure from seeing her evicted first and booed off the BB premises. Sadistic, yes but thats one of the reasons I watch BB!