Some conditions are only applicable for Content Items, like actions related to Permission Sets and Layers. Neither Permission Sets, nor Layers can be assigned to List Items. Nonetheless, conditions are not filtered by the Trigger Point Document Type. That means that you can create a Business Rule for List Items with a Condition that checks if a Layer is assigned. Picturepark will ignore these conditions, skip them and look for valid (e.g. available for List Items) conditions.