[@Rilla] That's one I tend to get often, but id be happy to clarify. In my experience, interrupts are simple ways to invalidate entire sections of an opponents post(ex: Ian shoots his gun at whatshisface. Whatshisface looks at ians hand twitch toward his gun, and before he reaches it, skullfucks him with his super move). It creates continuity breaks that the less experienced either do without realizing it, and in my experiences, is an often exploited system. 20 posts could add up to 2 seconds IC because each participant is essentially rewriting the same move over and over again to account for the opponent cutting them off.

I may just be cynical or something, but the above reason is the primary reason why, but there are others, but they are more anecdotal.