I'm guessing the same kind of people who don't understand the difference between 0.002 dollars and 0.002 cents (http://verizonmath.blogspot.com/2006/12/verizon-doesnt-know-...).

To be fair, they claim the adblock engine saw a 75% reduction in memory usage, and in the images they're showing the main browser process generally (I assume? I don't use Brave), or which the adblock engine is only a part but had a substantial impact on usage.

That is correct.

thanks for the clarification. is this 45MB reduction for the whole browser? or is this 45MB per tab?

"Brave has overhauled its Rust-based adblock engine to reduce memory consumption by 75%"

This only claims that the memory usage of the adblock engine was reduced, not the total memory consumption of the browser.