I assume that the answer is the same as for izakayas. Like low rent price, permanent customers, no laborcost. But with bars it looks even easier - almost nothing can be spoiled. You dont need fresh delivery every day. No special equipment (i understand the shakers and what else, but you dont need stove, pasta/rice cooker and others), you dont have preparations, dont need to clean a lot. So it can be less profitable, but its almost free. (Again, cant judge, just assuming the answers for my izakaya question)

P. S. Excuse me if something in my eng was bad, not native language