Love your work ynot - it's always very interesting and you have to be a shoo-in for new poster of the year!
I did have a few thoughts on this - please forgive my musings (and they're certainly not in any way intended as a critique).
If there's any relationship it looks clear that it's with the more attacking positions - Halfback, Fullback, Wings, Centres etc
That leads me to suspect that margin of victory is maybe not as important as simply the points (or in fact tries) scored by a team.
If for instance Melbourne win two games; one by 40 - 0, the other by 60 - 20, I'd think on average the games that they score 60 points in would typically result in a highly level of Fantasy points (despite the same margin).
It also lends to the likelihood that the backs are most positively affected by scoring points (positions 1-7 have scored 76% of the tries attributed to starting 13 players this year and about 81% of TA's), then add in that they'd also dominate the associated LB's, TB's and LBA's directly related to those tries plus typically GK's too - and it's probably a fairly direct relationship between a team scoring more match points in a game leading to more fantasy points for those try scoring positions.
In terms of the query someone raised about whether it indicates correlation or causation, I think it's arguable that it's both.
Attacking players scoring fantasy points for attacking plays is a direct result of them scoring those points - those attacking plays generate fantasy points that lead to actual points (and add to margin or total points scored). They are literally interlinked.
I wonder if there would be a similar but slightly stronger relationship between total team points (or even more-so team tries) and fantasy point averages with backline roles - it seems to make sense on an intuitive level.
I guess the big problem is that even if you can predict more attacking points to a particular team (match-ups), it's much more complex to predict statistically how those points will be distributed in a way that indicates a certain player is more of a value pick over a certain other backline player - e.g. Wing A is going to dominate 50% more than their price point over the next 6 weeks (in a team expected to score points), whereas Wing B is only going to average around their price point generated across the rest of the season.
Probably the most obvious way is with a highly variable scorer that is down on value due to a run of tough oppostion, but heading into a much more favourable draw, while playing for a team that is likely to take advantage of that favourable draw (a good flat track bully team like Souths springs to mind).
I wonder if at present the best predictors of good value opportunities are fans that follow most matches and have a good understanding of a certain teams attacking structures vs upcoming match-ups defensive structures/weaknesses