It specifically fixes the low-hanging vulnerability where P2TR implicitly exposes a public key through the key-path spend, which makes it vulnerable to CRQCs due to long-term public key exposure. So it does make Bitcoin more quantum-resistant, for taproot specifically, which may be an important stop-gap while the addition of PQC signatures is worked out. Though it should probably be emphasized that the new address format is not more quantum-resistant than the other modern address types, and is still vulnerable to short-exposure attacks, should they become feasible.