This would allow wallet operations like funding transactions with smart contract-based inputs such as LN, or any input the Core wallet doesn't know how to sign for.

https://github.com/bitcoin/bitcoin/pull/17211#issuecomment-933674310
/**
     * @return number of blocks to maturity for this transaction:
     *  0 : is not a coinbase transaction, or is a mature coinbase transaction
     * >0 : is a coinbase transaction which matures in this many blocks
     */
    int GetTxBlocksToMaturity(const CWalletTx& wtx) const;
    bool IsTxImmatureCoinBase(const CWalletTx& wtx) const;
    
    bool CanSupportFeature(enum WalletFeature wf) const override EXCLUSIVE_LOCKS_REQUIRED(cs_wallet) { AssertLockHeld(cs_wallet); return IsFeatureSupported(nWalletVersion, wf); }