This is a pretty good article and for the most part, should be heeded. It's quite rare for the audience of a chart to exclusively be highly-numerate people (and these people, who are often inundated with data, are not immune from being misled by poorly-conceived charts). It's kind of strange that the top-voted comment points to "better" advice while also directly contradicting the article's main point ("dual axis charts can often be a great choice").

I mean, certainly you have the right to add some color but it comes off like you are saying to ignore the article entirely in favor of your alternatives.