Well, it's 50% so it's rather significant. Add that with ESO+ 10% and ring of mara 10%, and you've got a nice boost there. Just activate it once you've found a nice spot, because it will only last 2 hours and constantly countdown no matter what you're doing in game. Need to get a drink? Logout. Need a dump? Logout. Someone knocking on your door? Shout GO AWAY. I think you can get a bunch of them for like 1k crowns, which is a much better deal than a single for 300, so I'd recommend looking into that.