The reason I didn't like it was because it felt like an arbitrary technicality. I could technically pick warrior but only use magic for the entire game. Thus, I didn't feel like a warrior, I knew I was a mage, but my character being labeled as a warrior just felt annoying. It was like someone telling me that I shouldn't be a mage because I was supposed to be a warrior. Again, I knew I was a mage, screw what some menu said. Now, your class is what you make of it throughout your entire playthrough. The only reason I could think it would be useful was to cheat the system and stay at level one the whole time.