I appreciate your perspective and points. I personally do not like the restricted movement of the smith machine. As a physical therapist, I want my patient to get comfortable squatting with load.

If the sole goal is muscle hypertrophy and building endurance, perhaps the smith machine is a valid option, but if you want to build a bigger squat, you need to squat.

As for the spotter, it is only needed if you are approaching failure, which is not needed for hypertrophy. It you are nearing max out to improve a squat or bench, you need to squat or bench as the exercise differs. If you strictly want to build strength in a safe environment without a spotter, than the smith machine is a great option.