I didn't claim it to be a good sporting rifle, for that it's crap! But for taking to war, I for one would much rather lug a 7 1/2 pound rifle around than a 9-10 pound dead weight like everybody did. And don't fool yourself, every ounce adds up, painfully so. The days of using the rifle as a pike were long gone by then, but house-to- house fighting and close range action were very much the norm, so a short, handy carbine was just the ticket- consider how many Garands were "lost" and replaced by Carbines.
As for the sights, the average soldier didn't have a clue as to how to adjust the sights for range or probably even used them- just looked down the barrel in the general direction of the enemy. In fact, battle doctrine of the time often dictated the senior NCO would set the sightsfor the troops, who were then not allowed to adjust them.
As for accuracy, with proper ammo they were the equal of any, at least good enough to hit a person at a couple hundred yards. That's been proven.
Plus the action is short throw, easy and smooth, and as strong as any.
Plus it had one more round than most everybody else!
Best argument is that most militaries of today have gone to the same principles: short, light, fixed or semi-fixed sights, small caliber rifles.
Just like the Arisakas, it's a victim of bad press!