Variance: Using concentric movements is simply another tool in your toolbox that can be done a variety of ways: different heights, different bars, or with accommodating resistance.
Supramaximal: Working partial range of motion movements provides the neurological advantage of allowing us to use loads that our above our current 1-rep max. This allows us to build confidence with weights that we aren't accustomed to handling.
Lockout Strength: We can specifically target our sticking points and vary joint angles that may be less favorable based on our individual anthropometrics.
Rate of Force Development: Improving RFD is important and by starting from a disadvantage (bottom/dead-stop) we're forced to utilize higher-threshold motor-units quickly.
Developing Tension: Max effort work requires the ability to create tension. This aspect of training is often forgotten. But with concentric movements we're forced to develop tension prior to initiating our movement because we're essentially starting from a disadvantage. We're also unable to use the stretch reflex.