Pros:
✰: Very useful to turn off addons mid-game ✰: Helps with my constant forget-ful-ness of turning off addons... ✰: Surprised this isn't part of the vanilla/stand-alone version of L4D2, this is very useful.
Cons:
✰: Only con is that I do need a con...
Conclusion:
Very useful when it you have addon dyslexia like myself, and you find yourself with an addon you want to disable, but can't without closing out and going back to the title screen. Even if it doesn't work as fast as some people want, it's nice because the addons you do disable, stay disabled. So you don't have to make a mental note to turn them off.
Pros:
Cons:
Conclusion: