NRL is definitely responsible for more than just the Telstra Premiership. State of Origin, Pacific Tests, All Stars, NRLW Premiership, Women's National Championship are just some of the events under their remit.
Anyway as for the NRL logo changes, what I felt was poor was that they part did some entities and not others... You have the NRLW and NRL Corporate logo which is a simplified version of the old shield, Origin & Roos which are untouched and then Telstra Premiership, All Stars and Pacific Test which is the new shield type.
It just feels like a really ad-hoc way of doing this. If they want the Premiership to be unique, that's fine, but don't reuse the concept elsewhere.
If they want the Premiership to be the new 'base' for the logo, then update the respective logos and make the corporate logo align with the new direction.