There's an obvious example in programming: one might read a lot about machine learning, without becoming a practitioner. Without actually doing some work, one's opinions about building AIs wouldn't be worth much.

What breaks down is thinking this dichotomy captures the state of play wrt knowing lots of things. One of course has to practice knowledge, if that knowledge involves practicable skills, if one wants mastery.

If one wants to know history, or philosophy, or... many of the actual large bodies of knowledge that exist... one needs to get comfortable very regularly opening books. That doesn't mean it's all that's required!