Mixing with pedestrian traffic is absolutely not safer for pedestrians. It's also way less efficient, it would take ages to bike everywhere dodging pedestrians and tables and chairs and trash cans and doors and plants and dogs and whatever else the fuck is on the sidewalk. Maybe where you live your sidewalks are weirdly completely empty and so it makes sense but where the rest of us live riding on the sidewalk is incredibly difficult and dangerous and slow. Seriously just go outside and use your eye balls and think about it for more than zero seconds. This shit is not complicated. Or since you clearly don't bike maybe go talk to people who do.