Moonclips can reload a revolver from any position, even if you're hanging upside down.
Moonclipped .45ACP revolvers have been around since WWI, when everybody acknowledged that, yes, the 1911 held more rounds, but the two big factories were set up to build lots of big revolvers, and it was quicker to change out the chamber reamer cutters and so forth on the cylinder than to gear up to build a completely different gun.
They kind of did the same thing with the three factories that were building pattern 14 enfields for the Brits - changed the chamber reamers out for .30'06 and make sure the bolt face works. Lots simpler to make an adjustment for the crew who'd been building those rifles and revolvers for years than to tear down a production line and start making a different gun.
And that's where the logic behind that gun started. I'd love one, and that's all the logic required now.