You can't withdraw bonus bets or bet credits, but you can withdraw winnings. Bet credits and bonus bets cannot be withdrawn, but they can be used to wager on other sporting markets your sportsbook has to offer. Some sportsbooks make you use your bonus funds or bet credits in one lump sum.
Bonuses are extra rewards paid out to you under certain conditions and wagering requirements. A wagering requirement is the number of times you need to play through a bonus before you're able to withdraw any winnings within a certain period.