True ebony, when properly air dried and seasoned for a number of years, is amazingly hard, strong, and stable - and quite wear resistant.
Knife makers have a very long history of using exotic materials from all over the world - it's kinda what they do. Sheffield makers loved sambar stag from India - dyed with logwood dyes from South America -- now remember that this was in the 1800s. They went halfway around the world for the antlers, then a third of the way around the world in the other direction for the dyestuffs. Buffalo horn came from the Orient. The old Sheffield makers also used cocobolo, rosewood, and Suriname snakewood (usually called letterwood back then) -- all from South or Central America. Ivory was no picnic to get a good supply of either back then -- they called it deepest darkest Africa for a reason.
Heck, today Case uses the shin bones from a particular breed of cattle in Argentina for its scales -- and as far as I know, Case has done this ever since they opened their doors way back when.
Interestingly, a lot of the materials that came to be "standards" for knife scales were long time favorites of luthiers too.