Anime soundtracks were the ones that introduced Japanese music internationally, and mind you, not every anime op/ed is Jrock. There are many types of genres that came from anime osts.

Before babymetal. DIR EN GREY, X JAPAN, THE GAZETTE toured foverseas first.

I dont think Jrock is better. But even Jrock stuff like Babymetal became only popular overseas after tons of small Visual Kei bands toured overseas