When tapping the “…” icon, the menu option are displayed. When using haptic touch (3D touch/Pressing and holding) on the “…” icon, the menu options are not shown.
When using haptic touch, it’s possible to select a menu option by pressing down once on the button and then dragging your finger upward to select a menu option. When your finger is released from the screen, the option is selected.
With: press, drag, release (1 click)
Without: press, release, press, release (2 separate clicks)
To see the difference, press and hold on the new tab button and drag your finger upward to select an option. The tab view button also supports haptic touch.
TL;DR Adding haptic touch support saves a click when accessing the “…” menu options.