The monorail is good for when going to trade shows at the convention center. Park/valet your car at a hotel/casino that's easy to get in and out of (like the Sahara or the Flamingo), then ride the monorail to the LVCC, thereby avoiding getting stuck in car traffic near the convention.
Keep in mind that the monorail is pricey ($5 one-way), so if there's going to be a few of you trying to get somewhere, you might be better off taking a cab. It costs about $15-$20 to get from one end of the Strip to the other.