I've had my advy wounded at "stealth" before ("many monsters in this area, you see many signs of them with your own eyes"- or something)
She only has 25/25 gear though.
So yes, the settings can be useful 
On max she would have probably been killed.
My advy on Dwilight routinely gets routed on the stealth setting. The second lowest, one right below the default. That's with 50/50 skill and EQ. I also hunt a lot in regions that are swarming with monsters, often with full-out monster outbreaks in progress.
