Actually, it seems it is not enough. My usecase: I open a fairly large diff file with many changes like
-bla bla bla a long line were some word was changed or maybe two
+bla bla bla a long line where some word was changed or maybe two
I want to be able to immediately see the changes, without reading whole lines and certainly without visiting the hunks. When Emacs highlights the change (there is only one above), I see it right away. Otherwise I have to scan the lines with my eyes, which is tedious and error-prone. Of course I can also hit C-c C-b on each hunk, but it feels like some sort of work I'd prefer Emacs do for me.