Is “The novel borrows the Buddhist Vajra guardian names to serve as errand divine generals” true?

Buddhism indeed has the Eight Vajra Guardian Deities, but in Chapter 098 of "Journey to the West", they are dispatched by the Tathagata Buddha to carry out the concrete task of escorting Tang Sanzang and his disciples back to the East, with their divine roles serving more for the plot of the novel. (Original text: 「即叫八大金刚分付道：“汝等快使神威，驾送圣僧回东，把真经传留，即引圣僧西回。须在八日之内，以完一藏之数，勿得迟违。”」 Source: data/raw/xiyouji/第098回.txt)