Why stuff a roast chicken with lemon, onion, and thyme?
Lemon, herbs, onions, and garlic too are all aromatics that infuse into the chicken as it cooks giving it a lovely flavor. It doesn't absorb the flavors enough to call it a lemon chicken, but gives the chicken some flavor depth and acts as an enhancement. Stuffing the chicken helps these flavors to infuse better into the meat than spreading them around. Salt and pepper,too, should go in the cavity.