object-fit vs background-cover

The image has css object-fit cover and a height of 35%.
The height of the image does not response to a change of the width of the viewport but to a change of the height of the viewport. The image is scaling and cropped by every change of the size of the viewport.

The image is a background-image with cover in a container of its own. The height is by the padding-bottom trick. Does not response to a change of the height of the viewport but to a change of the width.
The image does scale but is never cropped.