Curious folks have been trying different materials to strop straight razors since they were invented. If you look at the 20th century barber suppliers I see that 'leather' was widely experimented with different types of hides being tried. Bovine, horse, shell, seal, elephant, kangaroo !
Looking at vintage strops I've accumulated it seems that Shell was the premier material that the suppliers rated the highest. My point is, people in our timeline aren't the first to investigate the best for the purpose. I think 'leather' in its various families is the proven winner in terms of strops. Pasted strops are another category IMHO.