The most common use of noncompetes is just to discourage an employee from quitting their job. "Oh, you want to go for for unrelated firm X? Actually, legal says they're a competitor, because we're a huge conglomerate. So, you can't take that job. Sorry."

In this situation, the company doesn't actually care about the competition at all. The noncompete is just another tool in their toolbox to discourage you from quitting.