Can anyone tell the major benefits of this update apart from what I understand is to help induce a free market for transaction fees.  Won't it break the ability to accept zero confirmation transactions?  As there are currently methods to do so with great certainty that a zero confirmation transaction will go through the next block.  And also doesn't this break the core ethos of bitcoin being a pure push system only.  I've read the RBF transactions update is being merged into bitcoin core at the next update.  Isn't that a little hasty for such a drastic change to the protocol to be brought in so quickly.  After it took us a good several months to agree on re-increasing the blocksize.