Unlike Leaping/Bounding boots, these can be augmented, which could add better additional stats compared to what you could only possess with Leaping/Bounding.
Just a note, the Leaping Boots drop from BCNM's, and the boots that Leaping Lizzie drop are the Rare/Ex Bounding Boots which don't work for this synth for obvious reasons.
Kinda sad to see a reasonable comment rated down... Especially since it was most likely done by people who aren't aware that Leaping Lizzy did, in fact, drop the "Leaping Boots" in past times.
Its so you can carry more than one at a time. People camping LL would get one, craft these boots, then remain camping, instead of having to run back to sell the Boots. Personally i've seen LL pop 3 times in a row, so this enables you to have many leaping boots in your inventory
