[babarock]

The main reason for tagliatelle/pappardelle is to get "fresh" pasta. "Pasta Fresca" or "Pasta all'uovo" is made of different ingredients than spaghetti. It's usually soft wheat and eggs versus hard wheat (durum wheat, semolina) and water.

I agree that finding the right pairing of pasta and sauce does make a difference, but I would also say not to overthink it. Most italians will use whatever's available in the pantry, even if it's sub-optimal.