As an answer to the original question, I'll also add that desktop operating systems don't use a "hand" cursor for interactive elements: buttons, menu entries, etc. The hand cursor is fairly specific to hypertext links.
Not sure why websites would be different. If you want to convey, on mouseover, that elements can be clicked, you should use a hover style variation (like desktop OSes often do), and you should probably apply the same variation on
:focus as well. If you think your users would be confused by the lack of a "hand" cursor (which is a debatable assumption), you can of course be opinionated like normalize.css is on this topic:
* Change the cursor in all browsers (opinionated).