The tow/haul modes is sort of like an engine brake. Very helpful when going down hill. Tap the brakes and it downshifts to allow the engine to slow you down instead of burning up your brakes, Tap the brakes again and it downshifts further. Near my house there is a 8-10% grade for 5 miles to get to the bottom of the mountain. I use the tow/haul mode and hardly need to use my brakes at all. Even towing the car. I've done it without the tow/haul mode and could smell my brakes at the bottom of the hill. I don't use it on flat ground or even climbing for that matter. It's also helpful in stop and go traffic as the engine helps "brake" you. You can certainly stop a lot faster and use less brake.
No clue about your cushions.