User-defined conditions allow you to distinguish between used-defined variants.
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.
In this example the product names are the user-defined conditions.
