Here’s why:
First let’s talk about the “Single Tap”. I think by default the “Single Tap” is set to “Open Menu” which, well, opens the menu. Although I find it useful on my iPhone 8, for iPhone X I find it much better to set it to “Home” which effectively makes the virtual button the home button. And it works on the lock screen as well! You don’t need to “swipe up to unlock” any more!
I’ll leave the “Double Tap” empty. Since I made single tapping trigger home button, double tapping will be recognized as a double tap of the home button and will trigger multitasking, which works great for me.
Now let’s jump to the “3D Touch” part. Inspired by how the buttons in Control Center react to 3D touches, I feel it’s only natural to open the menu when the virtual button is “3D touch”ed. Feels really good every time when I hard-press to pop the menu open.
I could have left the “Long Press” empty as well so long pressing the virtual button will naturally trigger Siri. But since there is already a dedicated long-press-side-button action for Siri that is also convenient enough, I decided to change it up.
Long pressing on the virtual button is kinda awkward; there is no haptic feedback. So I would suggest putting whatever action that is less frequently used but is still useful. Also know that the time limit for a press to be considered a long press can be configured to be as low as 0.20 seconds, so a long press can actually be triggered really really fast! For me I think long pressing for multitasking is perfect when I’m lazy and don’t want to double tap. Another great option is for it to open the Control Center so no more stretching is needed!
I hope this helps improve your iPhone X experience!