[hug]

Sometimes you can, yes, if you are picking the lens with which a subject will be photographed -- you can get down as low as 9mm on 135-film area, and still buy a relatively rectilinear lens.

Sometimes you can't get a rectilinear lens, though: If I want to shoot wide angle on my phone, curvilinear will have to do.

Sometimes you don't even have a lens, you've just got a photo, and that photo is curvilinear.

Novel ways to adjust for distortion are always nice to have in the toolkit.

[TeMPOraL]

Sometimes you don't even have a photo, but rather a synthesized image that looks as if a lens was in use.

Sometimes, you want to have a system that's able to self-correct after you slap a random lens on it as it's working. Or, you're looking through a translucent material, which acts as an ad-hoc lens with unknown parameters, and you want to compensate on the go.

Point being, methods of on-line calibration without use of special calibration setup (like ArUco boards mentioned elsewhere) have a wide range of use cases and are always welcome.