The long and short of hunts is that if you want Sands/Oils of time(to upgrade weathered gear to i110), Mythology, or Soldiery, hunts are the most rewarding content in the entire game.

However, this isn't "most rewarding" in the sense of Brayflox HM Speedruns were the fastest way to get Mythology but bumbling around and doing roulettes and other content wasn't that much slower. This is "most rewarding" in the sense that it dwarfs all other options so thoroughly that an increasingly larger subset of people are concluding that there is simply no point in doing anything else. Therefore, there are lot of people doing the hunts and you'll have to work hard if you want to get in on the action.

B Rank Hunts are intended to be fought by a minimum of 4 people, A Rank 8, and S Rank 40-50(?). The sheer number of people doing hunts means that many more than these numbers will be going after the monsters, so the main difficulty is not killing the monster itself, but getting to it before other people kill it