12 years ago, I walked into a second hand eye glasses shop in India and they had one of these machines. It was amazingly effective. I felt duped by all the optometrist appointments asking me about A or B.
To me, the tradeoff of an expensive modern machine vs an cheaper iterative process seems logical. I think it's funny that a second hand shop has the fancy equipment... but they must know it sells glasses more effectively.
Here, the machine results are used as a starting point, validated by A/B but I don't know if the human part is effective or just theater.
Well, assuming the optometrist charges around $50 per hour, after 10 patients it would pay for itself. I assume the machine is simply cheaper, which is why it was used.