Not at all! Treats are a very effective and an amazing way of letting your dog know that he has done something you are happy with.
Treats can be used to 'lure' or help a dog do a specific task but they will be even more useful to you if provided only when or immediately after your dog has performed the task, before the treat is provided.
With this approach, you can with time use other types of treats to reward good behaviour, such as your voice, your touch, your affection, their kibble and water.