Your resume has multiple audiences, likely first being viewed by Gatekeepers like a hiring manager or recruiter. If you can make your resume more accessible to people who are not intimately familiar with what you do, it goes a long way.
When you can draw a clear line to what your technical change did to move a business metric, that's what you'd always want to prefer:
Increase cart conversion by 1.2% YTD leading to $45MM incremental sales by optimizing page interaction metrics
But there are plenty of times you just can't draw the line. For example, maybe you don't have the data to say "every 100ms costs 1% in sales."
You could still "explain like I'm 5" what the value expected was at a higher level, like:
Lower the time for users to interact with a page by 8% YTD for search and home pages, which helps increase add to cart interactions.
This at least helps describe why the accomplishment helped in terms someone who isn't familiar with the intricacies of page performance optimization will understand. Plus it's a conversation starter:
Interviewer: "Oh, did that lead to an increase in sales?"
You: "We didn't have the data to prove that, actually I was on a project to try and figure that out..." 😼
You are hired to deliver business value. When you can showcase how skilled you are with the Bow of Value and put it on your resume, it's easier to stand out in the sea of developers and get the next (better, stronger) job you want.
This Devsword's Scroll of XP says that they've been able to cast level 20 business spells like "Sales Blizzaga," summon them to our court immediately!
Take a look at your resume. Ask someone (maybe in your company) who is not a developer to read it and ask them to explain what it is that you've done. Can they? If not, you've got some wordsmithing to do.
Bonus: A high-level move is to have both a "regular" resume you keep public and a "technical" resume you only send for applications, tailored to the company.