Arguing semantics isn't going to prove anything. I don't know why you wouldn't use the best load available. I also see you studiously ignored the Hornady Light Magnum loads
Of course you must realize that the 7mm-08 is also available in light magnum loads.
Also there are distinct disadvantages to shooting a bastardized caliber. Higher ammo cost, lack of guns in that caliber, lack of bullet/load choices etc.
If you are so concerned about the cost of ammunition,why even consider the light magnum loads?They are more expensive.Besides the 7mm-08 is available in many rifles by many manufacturers ans there are many factory loads available.The 308 being available in more guns does not make it perform any better.Since there are many suitable 7mm-08 loads,having more isn't a big advantage.
Then again you were so excited about the 300rsaum.You would be hard pressed to find a cartridge available in less rifles and with fewer factory loads available.Make up your mind.