On the contrary, I think the passthrough will be one of the defining differences to other headsets for the time being. Not having anything to hold in your hand while you go ahead and do non-VR things in your real environment adds a layer of convenience that's hard to appreciate from product videos. The improved passthrough, as bad as it still is, is one of my favorite additions on the Quest Pro.
What other things and how often though? Is it worth it losing the improved precision of the controller (and adding so much more complexity and battery use)
I think Facebook should consider usign only 1 controller though (i know I do). Also, to put the battery in the controller and tether it to the headset to make it even lighter. If apple is using a tether then it's ok to do it
I wonder if passthrough can be done mechanically, by rotating the lenses to a hole
That really depends on what you're doing with the device I guess. For gaming, controllers will remain indispensable, and you're planning to disconnect from the real world for a while anyways.
For everything else, quickly being able to grab a snack or drink, respond to a phone notification or change the place you're using the device from reduce friction.
It might be enough to push VR over that "I don't want to use the device because I don't want to commit to not doing anything else for at least 30 minutes now" hurdle that still very much exists.
That being said, I have no doubt Meta is going to be able to get there in due time too.