- The comment is referring to a graph that used 10^6 on the vertical axis, which is a very common way to format graphs with large numbers (not just "lately"). It's also the default for a lot of plotting libraries.

- 10^n is more compact than million/billion/etc, more consistent, easier to translate, and doesn't suffer from regional differences (e.g. "one billion" is a different number in Britain than in the US).

I'm not saying it's clearly better than "million" in this specific case, but it's definitely not clearly worse.

Erosion of education makes basic scientific knowledge very trendy