Not necessarily. Smaller RPA under 2kg can be used for commercial purposes but you are limited as to where you can fly them and without a licence, would break rules. From a business public liability perspective, it would be much harder to insure as most RPA and business insurers will not cover commercial RPA for pilots without an RePL. As a professional photographer, you would want to fly wherever you want and know how to do that. The only way to do that is to be licenced. This also gives you creditability as a professional photographer.