Yes, it would help to know that I could see a dentist who would inform me of cavities and gingivitis that I am (or am not, depending on genes), developing as a result of my brushing habits (and through that feedback help refine said habits), rather than merely hoping and doing nothing more for lack of funds.

And many people will require regular teeth cleanings to avoid gum pockets and consequent gingivitis despite their best efforts at brushing and flossing.

There are other situations where tooth infections can move to the brain in a matter of days, risking death if left untreated. Regular checkups reduce that risk considerably.

The other side of your argument would imply that the existence of toothpaste renders the entire field of dentistry inessential.