It wouldn't make sense to transfer the bounty immediately - you (the system offering the bounty) want to keep open the possibility that the killer doesn't know about the bounty or gets killed before they collect it or for some other reason never completes your process to collect. Then you get your enemy destroyed AND you get to keep the bounty money. Double victory!
It's the same way that the Comcast help-line doesn't make it easy for you to quit their services. It is not in their financial interest to expedite the process of losing money. So they do the opposite and drag it out as long as they can, in the hopes that inertia will win, and a lot of the time it does! Profit$$$!
We (the pilots) are just lucky there isn't also a 3-hour queue at the "Contacts" desk to get through to the lone payment clerk working that day (but is currently on their lunch break) and who requires we have five forms of ID needed including a local-system residence!![]()
Best explanation so far, and well within lore.