I thought it was a commonly held thought that Google didn't want Chrome users using bookmarks because it directly competed with their search (and advertising).
Vertical screen space was very precious when Chrome came out. I remember their first feature over Firefox was moving tabs into the title bar and removing the menu bar, bookmark bar and bottom status bar, so saving about four bars of space for page contents. Since launch, they've reduced the vertical space of the tab bar/title bar, even as screens gained more pixels. Original design- https://www.google.com/googlebooks…
Of all of the terrible UI elements that have become fashionable, this is probably the one I hate the most.