In Jain philosophy, your intuition is partly right: samipya bhav (the closeness or association with gross matter) is not just about past karma in a vacuum; it is deeply tied to how karma binds the soul through raga (attachment) and dvesha (aversion).

Key points in a simple way:

• Karma and association: There is a strong link between what the soul associates with (matter, sense objects, emotions) and the kind of karma that gets bound. Being in proximity to matter tends to bind karma that keeps the soul entangled in the cycle of birth and death.
• Liberation is not about existing “in matter” while being free: Moksha (liberation) means shedding all bondage karmas and remaining as a siddha—a liberated soul. A siddha is not bound to a body and does not inhabit the conventional organic world. The siddha-loka is a realm of pure, non-material existence.
• Why travel to a matterless realm: The purpose is not to move to a place that is still made of matter, but to attain a state where no karmic particles bind the soul and no passions cloud the awareness. In that state, there is infinite knowledge, perception, bliss, and potency, without the constraints that a body imposes.
• The role of the body and world: The body and the material world are vehicles for karmic experiences. When the karmas that fuel transmigration are burnt off or shed, the soul no longer evolves through birth and death and achieves moksha. Thereafter, there is no further “travel” through matter because the journey of bondage has ended.
• Digambara vs. Śvetāmbara nuances: Both traditions agree on the goal of liberation and the non-material nature of siddha-loka, but they differ on certain doctrinal details about the exact nature of siddha, the timing of the release, and specific interpretations of karma. The core idea remains that liberation is liberation from matter-bound existence, not a continued, enriched existence within a material cosmos.

In short: Samipya bhav highlights how association with matter contributes to karmic bondage. Moksha is the turning away from all bondage, resulting in a siddha-loka where the soul exists in a pure, non-material state. The “purpose” of that realm is to be free of matter-bound limitations, not to re-enter a material world with a liberated, yet still non-material, identity.