Look in the mirror and ask yourself some questions and answer them honestly. Do YOU have the skills to hit a game animal the size of a moose or elk at 700 yards? If the answer is yes, then a 30 caliber magnum may be your huckleberry. If your skills limit you to 500 yards or less there are better options that cost less and recoil less.
If you exclude the large brown bear along the coast of Alaska that can top 1000 lbs cartridges like 308, 7-08, and 6.5 CM are adequate for everything else inside of 400-500 yards. The 30 caliber magnums aren't really an advantage on big bear, but they do retain energy at ranges that would make a 600 or 700 yard shot feasible if the shooter is good enough. And very few are.
I live in GA. Almost every hunter I know has had a 300 or 7mm magnum rifle in their possession at some point in their lives. While way overkill for GA game they justify it because they are going to hunt "out west" someday. Most of them never made it "out west", and the ones who did found the locals were using 308, 30-06, 270 and even 243 to kill elk. Those heavy, hard kicking rifles were eventually sold and replaced with lighter, lighter recoiling rifles that were cheaper to shoot.