so you're saying the nix playing at home at an empty stadium would have exactly the same metrics and play just as well as if they were playing at home in front of 30,000 people. That's fine.
As I said I don't know either way, it's just be interesting to find out if the croud does affect performance in any way.
I think the effect of playing at home is much greater than any effect of the croud. But I do think the croud has at least some effect, however minimal it may be. But again, I don't know for sure, it could be the croud has no effect, it could be they have a greater effect than I think it does, it'd be interesting to find out.
An example of players I can probably think of is the Bahrain playoff. Some nix players really pushed for that to be played at Westpac. That probably had a lot to do with it being familiar surroundings (effect of simply playing at home). But they also pushed for a sell out croud, they wanted to be playing in front of as many people as possible as they thought it gave them the best possible chance. That could have been just a marketing thing to try and get more money for NZF, or the players could actually feel a lift playing in front of a croud.
It'd be interesting to ask a player if they believed they play better at home in front of a croud vs at home in front of an empty stadium. I bet most would say a croud. The data would then show whether they actually did play better or not.
The other side of it is whether the away team has a positive or negative effect. If both teams get an equal positive effect, then the croud actually doesn't do anything for the result. If the away team feels intimidated (there was talk of the intimidating atmosphere the AWs faced playing in front of 100,000 people in their qualifier) then the croud does affect how well a team plays.
To re-emphasise (because you keep asking me): I have no idea conclusively either way whether crouds affect performance/metrics, but I'd be interested to find out. Any analysis would have to list its limitations, and wherever possible take other factors into account. I agree with you that this particular analysis seems to lack any context whatsoever and is therefore really quite meaningless.