Whenever I generate a rig, these collections appear. What are these?

Question

I have a few more question: Are these important when animating? Do i have to check the box? enable in viewports?

Answer 1

They are the widgets that you see in the generated rig. They're mesh objects, and the control bones in your rig are using them as their custom shapes. They don't need to be visible for this to happen, indeed unless you want to edit one you don't want them visible, because they'll just be sitting around in your scene getting in the way.

https://docs.blender.org/manual/en/2.93/animation/armatures/bones/properties/display.html#bpy-types-posebone-custom-shape