FWIW, many years ago I used to have a real problem with bleeding gums whenever I brushed my teeth (mainly around my molars). Flossing daily solved that completely.
Some people can just like brush once a day with a regular toothbrush and have perfect teeth, meanwhile some of us have to do scientific experiments, use sonic toothbrushes, floss, and use mouthwash or our teeth start falling apart immediately lol.