Traditionally, the motivation was to permit spending of both the “native” or “distant” dedication anchors, with out introducing additional extra pin vectors. It had many short-comings, together with lack of efficacy underneath adversarial situations, and nonetheless including substantial weight underneath even benign eventualities.
With respect to the number of pinning vectors and their historic significance, I do not assume I’ll do rather a lot higher than BIP431 motivation part for TRUC transactions.
Briefly, there are a selection of pinning vectors that existed when the Lightning Community was first rolled out. “Full RBF” was not adopted throughout the community on the time. RBF payment pinning, package deal restrict pinning, lack of package deal relay, lack of package deal RBF, and so forth additionally existed, making replacements too costly (and incentive incompatible) or outright unimaginable given sure situations.
Since Bitcoin Core 28.0 a lot of this surroundings has modified.
With the deliberate replace to “zero-fee dedication” channels, these issues are considerably decreased or eradicated, end in higher composability, and leads to transactions with decrease weight. There’ll probably be a single anchor output that’s 0-value (or the trimmed HTLC quantity), and Pay to Anchor (P2A) making it spendable by both counter-party with out a signature.
