> jump back and forth between pages quickly
You can't do it quickly. Jumping between random pages isn't useful (and not faster than in an ebook), so you want to jump to a specific page, and here ebook is much faster, whether you're opening a page number or a page with some content you remember
> know where to flip to approximately to start my search.
Or you can start precisely with an ebook
Of course it's not, you can't fit all the words in a book on index cards, you can't fit all the appearances of a given character in a story, all the memorable highlights- all trivially done at scale in a digital book. You can't jump from the index at the end to the required 5 pages where this term appears at the speed of a click
And then your highlights also can't unstick because there is some dirt that ruined the stickiness of a note. And your carefully prepared unsticky bookmarks (you didn't have sticky notes around, so you've followed your advice and improvised) can't all fall out just because your book fell with its back up
I'm not claiming that physical books have all the properties of digital ones, or vice versa.
But there are reasonable affordances to a practical extent within both formats.
I have a large print collection, and a much larger digital one, presently largely on an Onyx BOOX ebook reader. I'm well acquainted with the capabilities and limitations on both systems.
(I've discussed the BOOX device fairly extensively in previous HN comments for those interested.)
With the use of bookmarks (prepared or improvised with index cards, etc.) or sticky notes, precision jumping within a physical book is very quick, easy, and useful.