Mika might not influence the audience but Kendji was there because Mika liked him in the first place...
And to paraphrase your sports analogy, I hate it too when supporters say "we won" but Mika was not a supporter, he was the coach... The coach IS part of the team, he instructs his players. And who usually gets fired first when things go bad...
That being said, and while I really enjoy seeing Mika being part of this show, I can't see it as a huge accomplishment. Certainly not worldwide.
I'm much more delighted to see both of his OSM shows almost sold out.