In my opinion, soul-bound tokens (SBTs) are very much akin to certification systems and have a wide range of potential use cases.
SBTs and Non-fungible tokens (NFTs) may be applicable to different aspects of the same transaction. For example, in works embodying some form of intellectual property, NFTs may be used to create specific representations of a work while SBTs to attribute the origin to the creator. This concurrent use of SBTs and NFTs would conform to the distinction between use rights and the moral right of attribution.
Concerning the issue of decentralization, while SBTs as originally conceived give issuing entities a measure of power similar to that associated with centralized institutions, ‘claims’ as an alternative or improvement to SBTs would lack the evidential weight of an SBT issued by an entity that controls the concerned process/activity. Although there is a broader problem of subjectivity associated with certification systems, this would be more pronounced with extrinsic attestations distributable by a public key.
This also leads to the question, in relation to DAOs, whether some measure of centralization is needed or in fact inevitable. Again, the question surrounding the inevitability of centralization touches on the possibility of dystopian outcomes for specific projects and for DAOs as a new global organizational paradigm. With the permanent nature of blockchain records, if DAOs come under central control, then data would end up being controlled by a small and powerful circle.
As regards the permanence of SBTs, there is the question of how they will impact the right to be forgotten in some of their use cases such as credit reporting. In order not to totally eliminate the right to be forgotten in the use of SBTs, particularly with records that lose their validity, how can SBTs be revoked?