I disagree. The point is to save money by using an aircraft tailored to today's conflicts (and to be able to supply to allies), and to keep hours off the dwindling fleets of F-16s, F-15s and A-10s, and to 'season' younger less experienced pilots quickly and cheaply. The USAF is big enough to be able to afford a small but significant force of OA-X, which makes perfect sense, for them, to me.
I believe that the point is purely to deflect attention away from canning the A-10. The USAF says repeatedly that " OA-X is an experiment, not a competition", and that the capability assessment may not necessarily lead to any acquisition. Once the A-10 is gone, OA-X will go the same way to leave the USAF to follow its original path of having the F-35A perform the CAS role.
A wing of such aircraft in the RAF, for example, would be also be a great way of keeping a pool of highly experienced aircrew in Reserve/Auxiliary billets current and available for "surges".
The RAF didn't buy light attack turboprops when they actually had a use for them in Afghanistan, so there's no chance they are going to get them now or any time soon.