There is probably a good reason why the crisp off the stone feeling goes away after a few shaves and some stropping. I like the feel off different finishing stones, but films and and balsa does have a place.There is very little "give" in a properly constructed balsa strop when used with the pressure (or lack thereof) on a SR.
When a balsa strop is properly pasted, the diamond particles are embedded into the surface of the balsa with none "rolling around" on its surface. This greatly reduces the scratch depth on the bevel.
I dare say that there is little to almost no convexing of the bevel/edge when stropping on diamond pasted balsa that has been properly prepared and used. I would be more concerned about bevel/edge convexity being introduced due to stropping on hanging clean leather before each shave. The hanging clean leather has a lot more "give" in it that a balsa strop has.
As I have never needed to return a blade to a whetstone/films for refreshing the edge, I cannot comment on whether any convexity that may be in a blade's bevel/edge brought about by balsa and/or clean leather stropping affects the refresh result.
I have only rarely shaved of a 0.25μm diamond pasted balsa strop. On each occasion it gave me the worst shave compared against 1.0μm film, 0.5μm balsa and 0.1μm balsa.
The Iwasaki paper should have some appendices added to it and updated