Are buttons necessary on product cards?

Lately I've been seeing a lot of product cards without buttons. The idea is that the whole card is the button. Generally it looks card-like and clickable (has a drop shadow on the whole card). I have a few a11y questions.

  1. Is this user-friendly for sighted users?
  2. What are the potential a11y issues for screen reader users?
  3. What are the rules about links within a clickable space? (I seem to see it a lot, but I've heard it breaks some rules)

Obviously I recognize the pitfalls of not having a button, but it seems intuitive to me for a whole space to be clickable. When in doubt, click on it, right?! When my mouse hovers and changes, I know to click it. Maybe not everyone does. I'm wondering just how bad it is to remove buttons, or if there are issues I'm not thinking of.

I'm mostly referring to desktop, since product cards are so common on handheld. But I welcome any insights about handheld as well, especially the question about links. Product Card Examples