Not a rocket scientist or a writer but if you check the 300 WSM it's ballistics match the 300 Win mag but it requires 10% less powder which means slightly less cost, and less kick (check the kick equation it has the powder weight). Shorter action means stronger action = potentially more accurate gun. Powder burn's at a rate of feet per second and the powder gets pushed down the bore as it's burning. Since it's wider instead of longer you get better powder burn in a short fatty, than you'd get in a tall and slim load. Last but not least with slightly less case capacity you get compressed loads with more powders which is typically more accurate, and much easier to verify you have the right amount of powder by eye which is safer.
Bad stuff, less rounds in the magazine, but you should only need one shot anyway.
Spot.
