What's the reason to say get a 6.5mm-284 Norma over a .308 Win?

Do 6.5mm and 7mm bullets always beat out the .30cals or .338cals?

If 7mm bullets are better than 30's, then would a 7mm-08 beat out a .308?

Or how about the .260 Rem? Seems like this cartridge is dying, and the 6.5-284 is only getting more popular.

If one were to include long range hunting of say deer sized game or smaller what differences would there be to consider? I mean one doesn't need a 7mm RUM to kill a deer at 1000yds do they?

Also is the 6.5-284 a short action cartridge usually built on long actions? or can you still effectively shoot say 142gr SMK bullets out of a short action rifle with this cartridge?

Also would a custom rifle built for a long range setup in say 7mm Rem.Mag. shoot as well as a 6.5-284 in the same set up? Is it the gun? the cartridge? the shooter? recoil?

seems the long range target crowd tends to like short action beltless cartridges don't they?