You always have the choice of a conventional rod or a spinning rod when fishing, so when and why should you use a spinning rod for jigging? You can use both types of rods for jigging but using a jigging spinning rod is a little easier, especially for anglers who are just starting out or for anyone who wants a less stressful experience. No birds nests with a spinning setup.
Spinning rods can be a good choice if you are new to angling or to jigging too because they can be a little more forgiving. Spinning rods can be used for different types of jigging, even for slow pitch jigging, which is usually done with a conventional rod.
Whether you buy a casting or spinning rod for jigging depends on what you want to do with it. While a jigging casting rod is built for a conventional star drag or lever drag reel, a spinning rod is not. Spinning reels can be much easier to use, making them a good option for anyone starting out with jigging. In terms of budget, you're likely to find similar prices.