I mean, why would Scholz endure all these political pressure back at home to make this trip, just so Macron can tag along and scoop up all the freebies without sticking his neck out.
Macron's presence would tremendously complicate the visit. Macron is actually head of state while Scholz is not, between the two China will have to give Macron preferential treatment. Having two people like that also sets the wrong tone as it feels like a gang trying to pressure China, instead of a one on one discussion between equal.
Of all the EU leaders Macron in many ways is the one best equipped for playing geopolitical games. He is the head of a P5 nation and alone wields the nuclear stick in EU. He actually has a non-negligible military backed by a fairly complete MIC unlike Scholz. Yet whenever he comes under a bit of pressure he does this:
The Five Eyes steal his sub contract and he gets angry for like 3 days and back down. It's this aspect of him that I really dislike.