Sure, 10% would be a pretty big deal, but 1% in the right places is enough for a different outcome. As this article shows
Given the fact that Stein’s share of voters in 2016 exceeded Trump’s margin of victory over Hillary Clinton, Clinton would have won Michigan, Pennsylvania, and Wisconsin and thus the presidency, if Stein had not been in the race.
Now, I won’t assume that all those voters would have voted for Hillary had Stein not run, but it’s clear that third-party voting can have an impact on who wins, even if they have no chance to win themselves. But the GOP seems to think this could help them, and is willing to spend money on that chance.
Still more evidence that Daredevil’s superpower isn’t being able to navigate using echolocation, but to be able to take a beating (which he inherited from his father).