With RBF, I can look at the mempool and set the sat/Vb fee to the current minimum fee needed to be confirmed. As seconds or minutes pass, that fee may become inadequate. RBF lets me (or my wallet) increase the fee by composing a "replacement" transaction. This essentially assures me that my transaction will be confirmed in the current block (that the miners are trying to solve) without me having to pay more than was needed.
That's the good (for me). And that's what I want to see for bitcoin -- the assurance that time-sensitive transactions can be confirmed promptly, if I'm willing to pay.