This is a great illustrative example of why those numbers are informative - most developers are like you, and can't do that, but the reason is not in "CV writing" but in actual content of the work.

From what you say, it sounds like that whatever you did was driven by (initiated by, started because of) (a) technical need (b) order from above or (c) guessing. However, what people mean by "show the impact" is that they are looking for someone who has already done work mostly driven by their observations of business needs, their initiative to improve specific business results by technical means.

If you had no idea "how much revenue these features are going to help bring in or how many sales they'll generate" then you were performing a different role/function than e.g. a person who looked at a need to increase sales (or whatever else was the main business/strategic goal of their company at the time) and figured out a software feature to achieve that. Perhaps you are capable of more than just implementation, but how would a potential employer know? It's not like they'd just ask you, they want to see evidence that you have done this before, that you have been not only implementer of ideas but initiator of changes driven by your personal understanding of business needs - not matter how your role was called or what your nominal job description did/didn't include.