My theory about the Cryptics is that they gain power from hidden truths and that the difference between the name that they give themselvs and the names that others use has to with how one views the methods that they use to keep these hidden.
I imagine that this could be why they were so attracted to Shallan, she keeps so much hidden even from herself. I think that she will strengthen the bond between her and her spren by revealing some of her secrets to it leading into her flashback chapters.