I can only imagine what a ridiculous problem it would be to try to re-do, for example, the Vincenty formula for distance between two latitude/longitude points on an oblate spheroid (the earth) if it couldn't use radians.

https://en.wikipedia.org/wiki/Vincenty%27s_formulae

https://www.johndcook.com/blog/2018/11/24/spheroid-distance/

Further, inverse vincenty is pretty much an essential in anything that needs to find the azimuth between two points on a map. Such as for microwave radio link planning purposes.

Karney (2013) is also radian dependent.

https://github.com/pbrod/karney