> The image improvement was negligible with the main benefit being smaller file sizes.

That's a contradiction because quality improvement and file size improvement are just two sides of the same coin. You can't have a large quality improvement at the same bit rate without having a large file size reduction at the same quality.

Yes, I stipulate your point, but people are not looking for better encodes at the same bit rate. They are only looking for not worse quality at much lower bit rate. One project I was working on had a hard file size limitation, and switching to h.265 was able to get the size under the limit. At one point, I was told to make it smaller by X MBs. The image wasn't even being looked at with each change. This is why I make the distinction the way that I did.