When you need to call down the thunder to deal with those pesky biters, launch a rocket with an ion cannon into orbit and show the bugs who's boss.
Mods introducing new content into the game.
New ways to deal with enemies, be it attack or defense.
When your mod is installed with Space Exploration and KS2 it limits the amount of items an assembly machine 3 can use to produce Cargo Rocket Silos making them impossible to make in anything but Assembly Machine 2s.