It is depends on the type of the structural element.
For Beams
We provides links to carry the shear force and torsional moments. So we provide links to avoid shear failures and torsional failures. Torsional links are provided only if there are torsional moments
For Columns
Mainly links are provided to avoid the column buckling. When there are significant shear forces we provide links to carry shear forces. In addition we provide links to mainly the confinement of columns in confinement zone. This a earthquake detailing.
For Walls
We provide links to carry shear forces and to maintain the confinement.