You don't need to be very high to take fall damage. If I know there is a hill in front of me, with a flat edge on the other side, I find it easier to use my rocket boots to climb up it quickly, ivy whip too depending on the shape of the hill, then I'd just run off the edge of the hill, no need to conserve a little of my rocket boots to negate the fall damage, I can just run off and keep going. On my single player world, there are 2 large hills with corruption chasms on either side, so I find it easier to rocket boots up, land on top, then rocket boots across the chasm and let myself fall on to the straight bit of land.
The horseshoe is also handy for exploring new places, I can use my rocket boots as much as I want without leaving a tiny bit left to negate fall damage. It makes playing that little bit smoother. Sometimes I'll fly up as much as I can with my rocket boots to fight flying enemies, and hit them with my Night's Edge/Murasama, with the horseshoe I can keep swinging. Without it, I either have to conserve a little of my rocket boots, or use my ivy whip. And if I've been swinging with my sword on my way down, using my ivy whip means missing a swing with the sword. Also handy for hellshafts, the orb of light doesn't fall as fast as a player does, on a MP server sometimes people put blocks halfway down the shaft, if I can't see it then I'll die from fall damage.