Isn't it easier to roll out the pie pastry dough immediately after mixing the ingredients before putting in the fridge to rest?
Chilling your pie dough allows it to firm up, which actually makes it easier to handle. If you roll it out immediately, it may be too soft since the butter or shortening is a bit soft. If your dough is very hard when you take it out of the fridge, you can let it rest a bit and come back closer to room temperature if you'd like.
Resting the dough also makes the final texture more flaky.
It might be easier but your end product will tear in spots. Refrigerating the dough will allow the butter/water to distribute very well, and you'll end up with a nice, smooth dough to work with. When you remove the cold dough from the fridge, use the Julia Child method of whacking it with a rolling pin to soften, and then roll away..
No, it doesn't make it easier to roll. The resting process is necessary to let the gluten rest. If you roll it out immediately, it clumps and tears. there is no reason to roll out COLD dough straight from the fridge, though. There is no disadvantage (except perhaps time) to letting the dough come up to room temp before rolling it out.
Flour in the pastry dough hydrates during the resting process, bringing the dough together a bit more without overworking the gluten.