[SplineGod]

You dont HAVE to use IK. You typically want to use IK for things that have to stick to other things like the feet sticking to the ground. FK(forward kinematics) is a top down animation style like you would do with a stop motion puppet. You start from the root and work your way down the chain of bones towards the extremities.
IK(inverse kinematics) is the reverse of FK. You animate the extremity and the motion is propogated inversely back up your chain towards the root. This is more or less how a muppet is animated. There is a rod that connects to the wrist. Move the rod and the whole arm moves. You could also move the body, for example, and the hands and feet dont move.
Animating via FK is more tedious but more precise. IK is typically faster but not quite as precise. THere are ways to mix or blend IK and FK including a free plugin on flay.