The answer is really never, as it is a bet that will keep you from winning in the long run. If the dealer is showing an ace, there is about a one and three chance of them hitting blackjack and you are basically betting on a fifty fifty gamble. Say you take insurance 100 times for ten dollars each time. You have put in $1000 dollars overall, but the amount of times you'll win is 33, so you would get $667 back from these bets. Insurance against the dealer is called a sucker's bet and this is why.
The only time it is good to take insurance is if you are playing in a blackjack tournament because you are playing against other players. If everyone decides not to take insurance and you are acting last, you might take the insurance in the hope that the dealer has it and everyone but you losses money, but this is the only spot where it makes sense.
That game would be Black Jack the winning score is the closest hand to 21
Black.
The only thing that can cover in a game of blackjack is a dealer-blackjack.
To hit in black jack is to accept another card in hopes of getting closer to 21 without going over.
It is 8/13.
poker
Ten os bigger
Black jack
Black jack
In Black Jack, the Ace of Spades is worth the same as any other Ace, 1 or 11, as needed. It has no special meaning. A "Black Jack" is any combination of two cards that total 21, so it is any Ace plus any face card or ten.
The Shoe
It depends on the game. Which cards 'beat' others will be defined by the rules of the card game, whichever it is. Many games do not use the joker at all. Others, such as Canasta, treat it as a wild card. In Euchre, it is the highest ranked card.