However, the SIGHASH_NOINPUT would eliminate the need for this feature. Despite this, ZmnSCPxj pointed out that having the former would be useful for Lightning, as it would allow every funding transaction to include an OP_TRUE output. This would enable fee-bumping in case the initial feerate estimate is low, without changing the funding transaction ID. If OP_TRUE was not used for fee-bump, the alternative would be creating a new channel and Replace-By-Fee (RBF) the old funding transaction with a new higher-feerate funding transaction. ZmnSCPxj also mentioned that using the change output of the funding transaction for feebump might not always be possible.