I don’t clarify the butter, I just remove the water so I don’t think it’s actually ghee but I’m often wrong.
I’ve never used vinegar in pie crust.I’m not sure what acid would do for the crust. Perhaps it retards gluten formation for a flakier product.
I use a tablespoon of lemon juice instead of vinegar. Adding an acid gives the crust a more complex flavor, and makes the sweet ingredients taste sweeter by providing a contrast.
The prevent gluten formation, use vodka for part of the liquid.
For flakiness, make sure the dough is comprised of tiny bits of fatty flour interspersed among tiny bits of moistened flour. When shaping the dough, make sure to do the “fold-and-flatten” part at least 4 times. That way, the tiny bits are in thin sheet-like shapes instead of round lumps. When baking, the water in the moist parts of the dough will evaporate, and the steam forces the different types apart. If the dough is overmixed, the different types of dough become one type, and then they don’t behave differently enough to form flakes.
(I’m not sure I’m explaining that very well. It’s one of those things that easier to describe if I can sketch it out while talking.)