You decant wine to enhance flavor and separate sediment and whatnot. I don’t think there are flavor reasons to put whiskey in a decanter but it looks so cool. If you want to feel like you’re fabulously wealthy or an extra in Mad Men, get a decanter and fill it with whiskey. In my case, I also buy my everyday bourbon from Costco so the smaller, cuter container is a bonus for easy pouring, plus I feel classy and rich.
You probably shouldn’t store your brown liquor of choice in the decanter endlessly due to a less intensive seal than a bottle provided by the distiller. But once it is out and on display, you will *want* to pour yourself a drink more often, so that problem sort of solves itself. Georgia in NYC gets a decanter and glass set to add some elegance to her drinking game.