(Loadsaposts whilst writing. Look a dozen or so posts back to what I was originally replying to...)
It was likely a plan developed in Obama's time. There are
always plans sitting in a developed (or half-developed) state, because if you don't have plans (of one sort or another) for a
wide range of contingencies, you're going to be at a disadvantage when something happens and you can only start from scratch...
I'm betting this plan was pre-Trump, but probably an embryonic and/or 'generic' assault plan, with plenty of fine-tuning needed to fit to even the template scenario to the latest updates of intel. If it was ever
seen by Obama, he would have understood it as such. Maybe Trump did, too, but I suspect that (either way) it arose as "what kind of operation can you do for me, within a week, as a showpiece of <this kind of thing>" and was then hastily fleshed out with greater or lesser pressure from the top in order to set the wheels in motion. And that left it vulnerable to errors. He also now couldn't even
not announce it as having happened (deepest regrets to the relatives, yadda yadda, your son died for his country, yadda yadda, but we cannot reveal the details of the operation...) because the PR
is the thing about it. Military value? Less than the need to say something (however unsmoothly) happened...