Mostly it was aesthetics, but yes, a split-open pod may attract other things, only "other things" didn't necessarily get all of my pods last year. An interesting thing to note is that, just like when our skin splits open then forms a scab, a split-open pod will ultimately form a protective layer over where it split, as long as it remains on the plant. And yes, just like our scabs being dark, the protective layer on the pods are dark, too. My pods were destined for being cut open and dehydrated, so I just cut these away and kept the good parts. I saw unripe as well as ripe pods split open, so the age of the pod didn't seem to make a difference. Ripe ones I picked and dehydrated right away, unripe ones I generally left on the plant to let them mature, which is why I noticed them forming the protective layer. (I hate to call that a "scab" since no blood is involved, though I guess that's pretty much what it is.)
Another interesting thing is that different varieties responded to the excess rain differently. The Congo Trinidads were the first and worst to split open. A couple other varieties split, too, though not as badly. Others didn't split at all.