From the standpoint of Thor and others, attending the Hundred Days Banquet is only a secondary reason, and witnessing the scene where Shi Xiaolei accepts the little guy as his goddaughter is the main reason.

After all, when it comes to their relationship, they have more frequent exchanges with Shi Xiaolei, and they are more familiar with each other. In contrast, neither Thor, who lived on Earth for a period of time, nor Loki, who once recruited Stark in Asgard, were actually not Stark's best friends, and he died.