Earlier quoted context omitted.
Maybe because it’s a non issue. I saw that those improvements are in the order of micro seconds, while the transfer time of a page is measure in 1/10 seconds or even several seconds. Even a game engine have something like 15 ms to have a frame ready (60hz).
Lots of small improvements add up - the total performance improvement is 53%. That's significant. If you're the size of Shopify that represents a huge saving in server costs and improved customer-facing latency.
This percentage is meaningless on its own. It’s 4 ms shaved off a 7 ms process. You would need to time a whole flow (and I believe databases would add a lot to it, especially with network latency) and figure out how significant the performance improvement is actually. And that without considering if the code changes is not conflicting with some architectural change that is being planned.