My local casino introduced a special bonus rule with
1 Joker card inside 6 deck shoe.
Joker is effective only as player's first or second card.
If player's 2 card combination is Joker and A,10,J,Q,K, then natural.
If player's 2 card combination is Joker and 2 to 9, then hard 21.
Joker after split is effective.
If Joker is dealt to dealer or player's third or fourth, fifth....it is canceled, and next card will be dealt.

How much is the advantage of this rule?