(from another thread...)
Even if I thought the gun was accessible quickly enough where I'm sitting right now to type this, what happens when I get up to use the bathroom? What if I go upstairs to get some water? Odds are I'm not going to carry the gun with me... now I've occupied a hand I might need for whatever else I'm doing.
If I leave the gun behind and that's the unlucky moment someone breaks in, now there's a gun lying in plain view for him to use in his nefariousness.
Assuming a holster comfortable enough to let me drive for hours at a time or sit at a restaurant with friends for hours, it should let me lounge around the house without too much trouble.
It also means less administrative handling of the gun which means less chance to make a mistake of some kind.