Externally primed cartridges were known in the flintlock period and became fairly common in the percussion era, but of course by then were rapidly overtaken by fixed ammunition. That one, though has something I don't think I ever saw or heard of in both using a cartridge and automatically priming the pan. Neat.
The main problem with a cartridge at that time was that the cartridge was steel and did not obturate well, so powder smoke and residue clogged the chamber and soon made the gun inoperable. The use of a powder magazine for automatic priming had been tried repeately, but also had problems. If the fitting was not very close, there was the risk of a spark reaching the magazine, at which point the gun tended to disassemble itself rather rapidly.
Jim
