The Büchsflinte = cape gun and the lower grade drilling were the tool of the practical hunter, the forester and the game keeper. Guns to be carried all day while doing the other chores on their Revier = area of responsibility. Just in case a chance offers itself. Remember, a fox may appear anytime, just as a roebuck or even a boar.
So it was the only, general purpose gun for most German and Austrian hunters.
While the 9.3x72R was a blackpowder number originally, the 8x72R and the much later 7x72R were smokeless loads from the start. But the 8x72R culd be reloaded with blackpowder and lead bullets, just like the contemporary .32 Winchester Special. The 8x72R was brught out by Wilhelm Brenneke, Leipzig, in 1898 as his first proprietary rifle cartridge. Essentially a tapered down 9.3x72R case, it was itended as an improvement over the 8x58R S&S and the 8x57R 360, but a slimmer package than the 8x57IR to allow for slimmer drillings.