It depends on what type you have. If it is any form of coupon, the answer is no. When the guest cancels a reservation with a coupon, the coupon will not be returned. So do not book if you're unsure. Airbnb will not make an exemption. If it is the host or Airbnb that cancelled the reservation, it will be returned to the account, and can be used again.
If it is a travel credit, it depends. Sometimes, it is returned to the account if it is cancelled, or sometimes it is refunded to the payment method. There's really no way of telling. If the credit is refunded to the payment method, the guest will no longer have a credit to use when they book.
https://www.airbnb.com/help/article/1352/what-should-i-do-if-my-coupon-code-isnt-working