The paper contains figures like [1] or [2], which I think do add something to the written description (and obviously the paper authors thought so too, otherwise they wouldn't have included it in the paper). These visuals are quite useful when talking about what we mean by "spotted" (though the context is important and the article only spends maybe two paragraphs on the actual observation method, so there's some danger of misinterpretation)
I'm sure the authors and their institutions would be happy to grant the right to use the images in an article about the paper if somebody asked them. Publicity for the finding is in their best interest. Unless their publishing agreement with Nature restricts this, not sure how strict exclusivity is in those cases
In some cases, for some papers it might be possible to eventually get rights to the charts that would satisfy your own publisher's legal department yes. They'd have to jump through those hoops every time though, and time is money.
1: https://www.nature.com/articles/s41586-021-03869-6/figures/1...
2: https://www.nature.com/articles/s41586-021-03869-6/figures/7