In the field of translation, I've had many conversations with peers and professionals about the practicality of learning theories on translation studies and its application. What I'm about to touch on, applies to any career, any field, and any situation really.
Driving is a skill that is taught through repeat practice. But when you are faced with a different traffic lights system in a new country, in that split second how do you make your decision whether to turn, or not? To stop or to go? Without basic driving theories, you can still drive - but you are effectively one road hazard posing danger to pedestrians and other traffic users every second you are behind the wheel. Without some theoretical knowledge, how many of us understand why a car moves when we engage gear and step on the accelerator, or what happens when you need to apply emergency brakes? Why does your car spin?