This joint carries the burden of the whole body.

If it is unstable it will put extra load on the shins, knee, hips and back.
If balance up the body is not good due to core strength being weak then this in turn will put load on the ankle.

The ankle is however supported from above, but effectiveness does depend on a good foot structure, hence the importance of a proper Assessment to establish where the instability is coming from.

Below you can see left ankle weakness due to an injury/ break