Sabudana (tapioca pearls) come from the cassava tuber. In Jain dharma, many people avoid root vegetables and tubers because pulling up or destroying the plant model harms small living beings in the soil and the plant’s life is ended. Sabudana is processed from the cassava root, so it is treated like a root-derived food.

Because of this principle, a large number of Jains choose not to eat sabudana in daily meals. There can be some variation: stricter Jains (especially among Digambar and Shwetambar communities) tend to avoid all root-tuber foods, while a few households may permit certain vrat-day variations or substitutes during fasting, but the conventional practice is to avoid sabudana on ethical grounds.

If you’d like, I can point to a specific Jain Knowledge page that discusses the root-vegetable restriction and how it applies to foods like sabudana.