User-defined variants are a trick for pros when it comes to using cliptexts.
Perhaps you have several cliptexts which are identical except for the product name (or something similar), because they all refer to the same situation. Depending on product that the customer refers to in his mail, you're using a different text. With a user-defined variant you can put all of them into one cliptext for this situation and depending on the product name the right variant will automatically be chosen.
