Tips and advice to remember :
Sugar is optional, and this sugar-free pastry is ideal for savoury quiches. But for a fruit tart, I prefer to add a little sugar.
White vinegar is also optional, but has two benefits: it prevents the pastry from oxidizing, especially if you keep it in the fridge for several days. It also limits the action of gluten, so your dough will be crispier and less likely to warp during baking.
The first pause is essential, the second (once the tart has darkened) less so. But it does allow the pastry to relax, thus preventing it from shrinking during baking. So it's more a question of aesthetics.