Speaking of presentation, it's far easier to teach a beginner to cast a flat trajectory with spinning tackle than with baitcasting. Mastering the sling-shot type of cast used under boathouses and docks is also easier with spinning gear. Fishing manmade structure spinning tackle can make the difference in your level of success. If you can't get back under the structure, you're missing places where fewer people have made casts. With baitcasting reels you can still master this presentation, but one slip and you have overrun.
Spinning tackle is much more forgiving.
If you want to cast baits or soft plastics longer distances, a longer rod will help. Many of these casts are, of necessity, flat trajectories and underhand or side-armed so a longer rod just gets in the way. If you crank a reel with your right hand, adding a spinning reel to retrieve with your left can also give you a physical variation as you fish. Even though there are heavier lines for use with a spinning reel, I wouldn't recommend it. If you try to overload the reel with heavier line you're going to have to work much harder to make reasonable casts.