Of course, there’s nothing to stop you from using your normal rod, but you’ll probably find that your rod and gear take up too much space for long trips.
The beauty of a travel-sized rod is that it doesn’t replace what you normally use, but it’s there when it’s too much hassle to take your usual rod out. There are all sorts of rods out there, and you may find there’s a rod you want to keep in your vehicle for those unexpected fishing locations.