There's a factor here that seldom people talk about.
That is concussion. When guns are fired, especially large ones, a pressure wave goes through the air. This pressure wave also goes through your skull and essentially gives a microscopic concussion.
I notice how I can shoot a 22LR all day. But a muzzle braked 300 Win Mag on in an indoor range? I get fatigue after 15 to 20 rounds. Not because of recoil, but because the brake is directing the concussive pressure wave backwards towards the shooter very aggressively.
Shoot a 338 Lapua with a brake and then without a brake. It's a massive difference in concussion, especially for neighboring shooters.
My cans are used to mitigate concussion. I can shoot magnum rounds with little to no fatigue. It saves my sinuses and saves me a headache especially on an indoor range.
I have read that some shooters report hearing damage even wearing plugs and muffs. Because some rifles are so loud and have such aggressive muzzlebrakes that in certain scenarios, the concussion goes through your skull and damages your ear drum regardless of protection.
So I encourage everyone to buy suppressors not because of sound reduction, but concussion, headache, and shooting fatigue reduction.