We use "straight" to distinguish heterosexuality from homosexuality (or any of the other non-cis-whatever stuff that all of a sudden people are offended over). You don't have to ask 'would you like cold water?' if you aren't offering hot. cisgender is used to distinguish from transgender, which is nowhere in the article. ctrl-F it. I'll wait. Here, it's used for far stupider, far more insulting reasons:

Here's the phrase:

We could say, for instance, that gay cisgender men and straight cisgender women rightly share similar worries about aging and dating, since men of all sexualities are frequently youth-and-looks-obsessed. Conversely, straight cisgender men can put off long-term romantic coupling for much longer, if they are wealthy, powerful or successful enough to be attractive for reasons that outlast their waning physical appeal.

We could therefore say, for instance, that gay transgender men and gay transgender women rightly don't worry about their appearance... wait, what? Somewhere out there are people who are not concerned about their appearance?

Conversely, straight cisgender men can put off long-term romantic coupling for much longer, if they are wealthy, powerful or successful enough to be attractive for reasons that outlast their waning physical appeal.

Oh, right. Because everyone else is so shallow that they'll fuck a rich dude for being rich.

In this case, we use the word cisgender to inoculate the author against accusations of being a prejudicial shithead. And it's bullshit.