Difference Linked anim layer and linked anim graph

im using linked anim layer to inject animbp’s to my main animbp
works well and wanted to know whats the difference between using “linked anim layer” and “linked anim graph”?

with layer i see i can have a default behaviour in my layer , wich could also be implemented with “linked anim graph” by creating one additional animbp,
with “linked anim graph” i dont need to create an interface and behaves the same
so i dont see whats the advantage of using one method over the other.