Frogger on 12 March 2017
The blood moon is there so the game can respawn the enemies you've killed. This way you can infinitely loot the items, for example. If the game didn't do that, it would be possible to run out of things to do, and resources specifically (like weapons). I'm not 100% certain of this, but it wouldn't be surprising to me if mining spots respawn during blood moons as well.
Now the game doesn't have to do that specifically, they can just respawn the enemies off screen, but Nintendo has a habit of giving a meaning to everything, so this was them doing that to make the game more immersive, which it does. It's also very clearly a call back to the three day cycle in majora's mask. Wouldn't be surprised if NPC routes are scheduled to that as well.
