The decline pullover is one of the most effective variations of the standard pullover exercise. Unfortunately, when performed on a traditional decline bench, it minimizes one of the key benefits of pullovers: core and abdominal recruitment.
Although the core is still working during traditional decline pullovers, the intensity of activation is less than in other variations where the legs are free, mainly because the legs are simply hanging from the decline support pads.
The glute bridge pullover, however, allows you to get more core and ab work.