I wanted to give this an honest chance. When I got my 16 Pro I quickly realized it was much easier to use this "upside down" with my left thumb than with my right index/middle finger. Then I quickly realized it was much easier to use it only as a shutter and deactivate the light presses. Then I quickly realized it was much easier to use it only as a launcher and use the onscreen shutter instead. Then I quickly realized I was accidentally launching the camera too often and switched to a double press for launch. Then I quickly realized a double press of this button was no better than, and in some cases worse than, other ways of launching the camera. Then I quickly realized this was even worse than the Touch Bar and maybe the biggest flop of an iPhone feature ever. Even 3D Touch was better than this. It's really bad and I don't know how Apple thought this was a good idea to not only release, but make it sound like a panacea for iPhone photographers. It's really that bad, and I was wishing to prove the haters wrong, but I just couldn't.
edit: the best thing I can say about it is they allow you to tailor as much use as you want into it, or completely turn it off... in that sense it's fine they released it as an option for those who like it, and I just hope they make it more useful down the road through software.