Does it just make it easier to get in a position you want or does it give you more natural looking positions as well or any other benefits? It's pretty fun to play with!
Imagine a character walking with forward kinematics. Every time you move the characters hips , you’d have to rotate the leg joints and make sure the foot doesn’t slide. Remember virtual characters don’t have friction.
IK lets you lock the foot in a spot so you can animate the body above it without having to spend time matching the foot position.
In a real world, this is like if you tried to put your hand on a door handle while jumping up and down. It’s easier to keep position when you hold the handle than if you were to just touch it.
You need a proper motion controller on top to actually have realistic walking motion driven by steps.