For the purpose of answering/explaining this, it does not need to be restricted to strains (i.e., it can be stresses too). I am mainly trying to understand when to use which one (i.e., if I am designing something, when would each be important to consider)?
Also, for a 2D case, where all strains are restricted to the plane, are they equal?

Abaqus ​​​​​​​