Big modded environments typically have around hundreds of mobs. Some of these mobs clog the spawn rates and crush the passively spawning ones.
This leads to a repetitive same boring mob spawns. Instead of configuring every single mobs spawn rate hand by hand. This mod automatically does it.
It even has some cool configurations!
Specifically made for Linggango Modpack. Using it on your own can cause issues. You are permitted to use freely though.