Most of the egg tart shell recipes you get are an iteration of a shortbread dough, which is yummy and quick to make, but tastes nothing like the actual tart shell. It is in the shell that you know whether someone is a true egg tart fanatic.
But as laborious as it is, it is actually the crust that is the 'make it' or 'break it' part of an egg tart recipe because anyone can make the custard portion. Chinese egg tart shells are similar to puff pastry and making a good and proper crust can be quite laborious. This is because it's one of the harder recipes to make. No one ever shows you how to make the shells of Chinese egg tarts.