I own everything I have seen in this thread and lots more, hands down the 300 blackout/300 whisper/300 Fireball/.221-300, as far as overrated goes but I have killed stuff with it, so even it works.
I am sure if you find the right liar, a squirt gun is all you need for water buffalo, so I'll leave the "for what" argument to them.
I think the posts listing ones that have been in use and have worked, for that matter continue to work, for longer than the posters have been alive, likely their parents too, are pretty funny though.
Reminds me of kids thinking "old stuff" is somehow inferior despite knowing how the old (or new for that matter) stuff works.
12 ga has been around since the 1800's, 30-06 and 45 acp are both over 100 years old too.
There are folks that are dead now that thought they were over rated but Betamax, VHS and Laserdisc were the future of cinema. Some likely thought 3 wheelers would be the end of motorcycles. All of them would have never thought people would pay more money to buy water in a bottle, than fuel...you never know about folks though.