Eh, I know posturing like that is taught a lot as a counter to the common Plum clinch, but there are other effective (IMO more effective) methods that don't require the same degree of neck/hip strength.
That said, hip and core strength are pretty much beneficial for any athletic endeavor and definitely so for fighting. This strength allows you to effectively connect your upper and lower body into one cohesive power unit; without it your techniques will never work the way they should.
Like Donny said, don't over complicate things and try to get too specific (outside of your actual sparring/drilling). Traditional free weight exercises (squats, deads, ohp, bench, rows, roll-outs, etc...), Oly lifting (clean and snatch variations), gymnastics strength training/bodyweight exercises, "Primal strength"/"Dinosaur training"/strongman training, pretty much anything that can be used to systematically and progressively overload the musculoskeletal and cardiovascular systems to illicit positive physical adaptations.