The first approach underlines a scenario where users refrain from co-spending inputs, leading to a constant increase in the number of UTXOs due to the generation of new change outputs with every transaction. This practice, although it seems straightforward, is deemed unsustainable as it results in an infinite accumulation of UTXOs over time, including smaller, less usable amounts known as dust UTXOs. These peeling chains of transactions facilitate easier analysis and tracing by blockchain analysts, posing significant privacy concerns.

Conversely, a "max greed" policy is discussed where users spend all owned UTXOs at once, effectively reducing their UTXO count to one under certain usage patterns. This method's sustainability and efficiency heavily depend on the user's transaction habits—merchants receiving payments frequently would see their UTXO counts consolidate significantly, whereas consumers engaging in rare, large deposits followed by numerous small transactions might maintain a minimal UTXO count. The introduction of the CISA incentive, though not explicitly detailed, suggests a push towards increased co-spending behaviors, potentially mitigating some of the drawbacks associated with both approaches depending on the user's specific transaction patterns.

The discussion then shifts towards the implications of CISA on privacy, arguing that while CISA may indirectly encourage practices enhancing transactional privacy, such as the creation of transactions by multiple parties, it does not directly incentivize privacy-preserving techniques. The cost benefits of collaborating to form a single transaction are acknowledged, yet the relative ease of creating non-privacy-enhancing transaction patterns under CISA's framework is highlighted as a potential drawback. Furthermore, despite the theoretical privacy benefits of complex transaction formations, practical challenges such as the coordination among users and the technical difficulty of implementing such solutions in user-friendly ways are identified as significant barriers to their widespread adoption.