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.

https://github.com/TheRook/bip-pubref/blob/master/bip-PubRef.mediawiki

The variant of this technology on the ethereum side is Ditto Transactions:
https://ethereum-magicians.org/t/eip-ditto-transactions/4455