1) Useful for vertical spacing for content. The spacing of two paragraphs become natural.

2) It's precise to build the paper line effect with a background-size: 100% 1lh;.

3) When the image should scale, the lh is perfect to align the image with an amount of line:

.content img {
  float: left;
  height: calc-size(auto, round(up, size, 1lh));
}

Note calc-size is not widely supported, so let's build an alternative:

.content img {
  float: left;
  aspect-ration: 1; // put the ratio of the image here, or remove a `width` limitation
  height: 5lh
}

4) Faded content with a max-height
5) Size an icon based on the line height