The only (possible) argument I can see is if some has a standard 280 and they want to spend the money on re-chambering because they are wanting more velocity. The reality is you're probably only going to see less than a 100 fps gain and even at that, you're on the verge of hot rodding the Ackley. If a guy has a 280 and wants more velocity, than build a 7 mag. The guy who probably had the most influence on the 280 Ackley's popularity, at least in fairly recent times, was Kenny Jarrett. I called Kenny Jarrett many years ago and got a copy of an article he wrote for Precision Shooting. In the article, there were 5 loads he suggested, one for 140's using IMR-4350, and the load in my rifle was warm (hard bolt lift).
