I think it's branching outside of just the diehards due to the increased popularity of supercoach and fantasy football.
I pretty much watch all 8 games each weekend because basically every game has some sort of supercoach related aspect to it.
Supercoach diehards tune in to trial games to find out if players will be in a new position heading into the next season and how they look.
Just at the Broncos people will be wanting to know if Riki is getting that second row spot, who's playing left center or left wing, will Asiata start at lock, how's Milf and Dearden look, who's got inside running for fullback, etc.
And that's just Broncos... people will tune into other teams as well so I think the NRL really is missing the jump not streaming trials properly