I call myself jokingly a "tofu vegetarian" because I became adopted the ovo-lacto vegetarian diet back in 1989, during the era where vegetarian cooking involved lots of tofu. That's when I discovered nutritional yeast for the first time. Back then it was hard to find, usually in one of the bulk bins at some hippy food co-op. But it's been my condiment mainstay for nearly 30 years.
My favorite uses for it involve pasta and popcorn. One of the quick, junk food lunch mainstays of my diet over the years was buttered penne noodles and nutritional yeast. It provides great umami flavoring to dishes. I eat less pasta now, but sprinkle it liberally on pasta entrees, popcorn, entrees that need a kick, and stir fry, It's a good sauce thickener and binder like a healthier version of corn starch.
Nutritional yeast is popular among vegetarians and vegans, in part, because it's an excellent source of vitamin B12, which can be scarce in these diets. But most people who aren't vegans and vegetarians can lack B12. Nutritional yeast is just an excellent source and is delicious and versatile.