There can be a lot of structure very near your transducer, and that can lead to sonar signals bouncing all around
But to be more particular, I think this really helps with either super light baits, when you expect to get an overrun (like throwing into the wind) or super big baits that just pull line like crazy when you cast them
With a low-inertia reel, though, you don't need a fancy cast - all your normal casts work with UL lures
A lure working appropriately goes through the accompanying cycle: It rises to the top, grabs air, breathes, jumps down, leaving a long air pocket trail, smoking, and when it quits smoking, it comes up for another breath
Hegy gets all that
They are often harder and more resilient to abrasion