if the Competition is driven by self betterment and self development then it's fair and healthy and it would definitely bring some good outcomes. But if it's driven by toxic ambition, envy or hatred - it will only do harm. and the second kind of competition kicks off the things cheating, lying and other unethical activities.
and i agree with @dedicatedguy - the education of possessing a healthy mentality comes from the family. home should be the place where you learn to compete in a fair manner :)