Wordpress is good at serving essentially static content so that part seems reasonable. The jQuery team is good with JS so node makes sense for building backend services. The service itself is not complex and probably doesn't have huge scaling concerns. Essentially performs a git pull when triggered by a webhook.
Wordpress is good at serving static content? Web servers are good at serving static content. Wordpress is a huge, monolithic CMS with vulnerabilities appearing frequently, thus I would call it rather bad at serving essentially static content.
