It does make perfect sense to me that you must wait to award the Bounties for all of the reasons except the last (see image). If there is an existing answer on an old(er) question which has helped me and I want to reward it with more than the +10 upvote, why should I have to wait in this scenario?
I would like to see this Bounty reason have no waiting period before I can award it to someone.
However like always I'm open for discussion about this feature request.
Image of the bounty popup for reference.