what does this line mean?

number of columns?

how the component works right now is to support one basic layout:
image on top, then text, then optional action buttons.

some custom content can be put inside/in place of the text, and stuff can be stuffed in the top image as well

for other different kind of content there is the "empty" card which is just the white rectangle with shadow, which then becomes completely the app's responsibility on what layout to use in it

Changed the suggestion to be more clear.

I would add a implementation section in another patch, and give hints for devs about the existing layouts there.

I would like to recomend instead to use the standard layout, the one that has a component (image on top, then text, then action buttons) and exampes where something completely custom would be used instead

"Use a lot" sounds a bit too strong (I don't think we want people to overload their cards with visual fluff just because the HIG said so)
Suggested rephrasing:

Use images, icons or video elements to create visually immersive cards.

ration -> ratio