Because that symbol was used as a notation symbol in those star charts and azimutal maps?

The article quotes the Didot system, specifically, which focused on printing travel maps and is known not only in the French speaking world for its timely accuracy [1] as it was also using that very same map system.

Maybe read the article next time?

[1] https://en.wikipedia.org/wiki/Didot_family

[2] https://fr.wikipedia.org/wiki/Histoire_g%C3%A9n%C3%A9rale_de...