Simone Weil is not a Christian mystic. She’s not Christian period. Nor Jewish.
Often called a Christian mystic, nothing could be further from the truth. Wikipedia labels Weil’s “school” as “modern Platonism,” which is only slightly less misleading. Weil developed a post-Christian, post-Western theology in her later work. Lissa McCullough argues that Weil’s universalism can be characterized as religious pragmatism, and that seems about right
Religious conceptions prove their value by their effectiveness in bringing about an attitude of amor fati — perfect humility, obedience, longing for justice, and action that is consistent with the ineluctable truth of finitude and death. (p 236)
Weil was particularly interested in Buddhism.
Weil is a harsh critic of the institutionalized church, likening it to the Great Beast, a collection of egos bent on the sanctification of their satisfaction.
Not your ordinary Christian
The crucifixion of Christ is where force meets submission to force, and submission is made holy. Weil shares this view with several contemporary theologians. God wins by losing, Christ’s power made perfect in weakness (2 Corinthians 12:9). The incarnation and crucifixion are enough for Weil. Resurrection spoils it; sacrifice not salvation is what religion is all about.