I really think your goal should be what you want your goal to be. Your therapist can make suggestions based on experience with you and other clients, but ultimately your goals and decisions are up to you. I consider autonomy to be more important for a therapist to encourage than practice-dating. I do see your therapist's point about practicing, but personally I wouldn't waste my time on a date I don't want. I don't know if it's mean or not to go on a date and raise the guy's hopes. It depends on his expectations too, not just your actions. This sounds more like a matter of what your values and needs are at this time.