The sender questions the utility of sibling eviction, which is a scenario where a 1p1c package can replace another package with the same parent transaction. While sibling eviction provides a temporary solution similar to Child-Pays-For-Parent (CPFP) carve-out, it is not sufficient on its own to address the issues of pinning in LN or creating zero-fee commitments.

The primary concern is that without package RBF, resolving pinning within the Lightning Network remains an issue. Pinning refers to the undesirable situation where a malicious actor can broadcast a low-fee parent transaction, effectively blocking any child transactions from being confirmed promptly. Package RBF would allow users to replace such transaction packages with higher fee ones, thus enabling them to outbid the malfeasor.

Additionally, to achieve zero-fee commitments in LN, there is a need for package relay, which facilitates the bundling of multiple transactions into a single package that can be relayed and confirmed together. This mechanism is crucial for LN channels' efficiency as it allows for commitment transactions with zero fees to be confirmed without being outbid by other users' transactions.

In conclusion, while sibling eviction might offer some advantages, it cannot serve as a comprehensive solution for the challenges faced by the Lightning Network. Both package RBF and package relay are necessary to enhance the robustness of LN's transaction handling capabilities, particularly in addressing pinning and enabling zero-fee commitments.