You learn so much from SEEING, whether it be from life, or imagination, or a photograph, and you may come up with very different results… but, if you are thoughtful about it, NO METHOD OF REFERENCE OR INSPIRATION IS INHERENTLY BAD! Any method you use might - by itself - be limited in what you can learn from it, but none are bad. Just pay attention, and you will notice if you are using something as a crutch or if you are no longer really being helped by it, and then you can do something else, use another method.
Trust your own experience. Learn from what you can. If someone says: don’t use photos, ever… don’t look at comic books… don’t use the computer to paint… They are only putting up walls. Perhaps they have wisdom about other ways of learning that you can benefit from, but do not let them keep you from finding your own artistic path. They cannot know your destination in art anymore than they can know your destination in life, and the paths you must take are yours to choose, not theirs.