The attached BIP describes a new opcode that unlocks the ability to have transactions that are about 37% smaller than a traditional single-source segwit transaction. (Savings vary based on the number of inputs.)
The pursuit of smaller transactions is vital for Inclusive Accountability as less data needs to be recorded on chain. Frugality is improved in two ways; more transactions can be confirmed in a block, and small value inputs otherwise inaccessible can now be referenced without losing unrecoverable value due to transaction overhead.
The variant of this technology on the ethereum side is Ditto Transactions: