Well, it seems pretty silly to sneer at Japanese products, particularly where things like manufacturing tolerances are concerned. But hey, whatever floats your boat.
Why have a single shot? How about:
1) Just to be different? Not everyone wants to be part of the Remington 700 crowd.
2) The notion of "what one needs (e.g. for hunting deer), and not a bit more"?
3) A shorter rifle without the drawbacks of a shorter barrel?
4) A lighter, trimmer gun, easy to carry?
5) No need to limit cartridge length to fit the magazine (some bolt guns force you to seat bullets far from the rifling).
Just think of it as the opposite end of the spectrum from hunting with an H&K MP5.
One mistake it is possible to make, I think, is too large a caliber. I had a Browning Low Wall in .260, which is not normally thought of as a kicker, but with the hard, small buttplate and the low weight, it was actually not that much fun to shoot, so I sold it. I now have the same rifle in a wildcat caliber, 6.5 TCU, which is a lot more fun.