If you miscue on a break with or without chalk then you've got bigger problems. You should never be so far off from center ball hit that miscues are even a possibility while breaking.
I stopped chalking my phenolic tip for breaking a few months ago and it's actually helped my break because even if I'm unintentionally slightly off center ball hit, the lack of chalk keeps the generated spin from being transferred to the cue ball. I'm never so far off center that I miscue...unless I'm drinking too much.
That being said, if you use a softer break, maybe like a second ball break in 8ball, you may want to chalk up so you can apply a little bottom right to the cueball. But on that note, if you use a softer break there's no reason to be using phenolic.
Good topic.
-Rob