ux designer – Doubt card design

I am with some doubts about the design of cards. I am using bootstrap and there is a card that has an image at the top, then a title, below the title, a summary and below the summary, a button like the "Read more" button. My question is if there are some good practices or something about the summary and the "Read more" button.

My question is whether the summary text is necessary since it is usually a very small text and makes the card longer. In terms of UX, there are some good practices on whether this summary should exist or not. Or is it really UX but is it just a way to inform the user a little more about the content of the article?

I also have doubts about the "Read more" button, for example on the home page, if there are 8 cards and each card has the "Read more" button, does not it make much sense or not? It is better not to have a "Read more" button and the entire card itself is a link.

Card with title, summary and button: http://jsfiddle.net/kzatw2r6/

Card with title and summary: http://jsfiddle.net/kzatw2r6/1/

Card with unique title: http://jsfiddle.net/kzatw2r6/2/