The company is still in business:
http://www.jagdwaffen-just.at/
Maybe they even have the old records?

This gun might have been built as a showpiece, but I do not think so. Why put valuable effort into something that has no real market any more?
One might also think about a "master piece", required by the European guild system to become a master gunsmith. Same question, a yourneyman would rather put his money into something that can be sold if needed. Also the piece should bear his name then, and not the company name.

I think the gun was made to order for a rather wealthy and conservative customer. Bear in mind that before WWI black powder express cartridges were still widely used and perfected. Many hunters did not trust small caliber jacketed bullets and smokeless powders, especially in break-action rifles.
Intended use - who knows? Maybe Africa, maybe bear hunting in the Carpathian mountains?

Fuhrmann