One use case is that I can pass in the value to a hidden fields that helps determine source, intent or other attribute of the subscriber as well as set it with a default value if none is set. One example is to have hidden fields for UTM values.
Another even more common use case to pull custom field values from the form, Phone number, business name, budget size, purchasing authority, etc… right now, from what I can tell, the only thing someone filling out the form can set into custom values in Moosend is name and email. Everything else must be essentially constants set at the time of form design. Please correct me if I’m wrong.