What is the need for WPF when we had windows forms?

A - Anywhere execution ( Windows or Web)
 
B - Bindings ( less coding)
 
C - Common look and feel ( resource and styles)
 
D - Declarative programming (XAML)
 
E - Expression blend animation ( Animation ease)
 
F - Fast execution ( Hardware acceleration)
 
G - Graphic hardware independent ( resolution independent)
 
I would strongly suggest you see the below video which explains all the above A to G points practically.