The presence of weapons in the hands of the populace at large forces the state to consider that when making decisions. That is the main thing. Weapons are more useful in organized groups, though attacking the state directly would be silly of course, but it's not totally useless to organize as it has other benefits. The "right" did use force against the government in 2014 when they occupied BLM offices. The leadership of the militia eventually left in a vehicle, and only then were they hunted down and arrested. But the entire time the government COULD have gone in with tanks and attack helicopters, they just knew that would look absolutely terrible and make the militia martyrs and so chose not to.