There are many reasons to order a custom stem. One, is you can clear up space on your handlebar by having the mounting system for your bar bag or bell integrated into the stem. Another is you can match the color scheme of your bike. Also, you can make it fit a vintage bar, which have different dimensions than modern bars.
But wait there is more...
The Plateau Rando Mounting system is free with the purchase of a Plateau Rando Bag!!!