I'm sad to hear about your experience. Let me address your points:

The button appears on hover and after translations and is translucent. You can also turn it off entirely and translate your images with shortcuts, Torii will still work without the button. Also what would you prefer? No button? How would you like to translate images?

While untranslated text does happen sometimes, it's very rare. Regardless, machine translation is simply not perfect and OCR is a difficult problem in and of itself. Sometimes texts have a weird font or size and can't be detected.

As for the translation taking 2 credits and not finishing, that should never have happened and had you contacted me I would immediately refund you your credits if that were the case. I am very available for anyone to contact me and there are 300 members on my discord server where you can easily and instantly contact me.

I e also experimented with rewarded video ads as you suggest but it's really not easy to implement and I don't think it's worth it. Torii has 2000 happy paying customers who use the extension daily and they rarely have any problems. Torii makes 30,000 image translations per day.

In any case, there are many extensions similar to Torii but we are definitely the highest quality and most stable one. That's why I'm disappointed in your review. I don't think you can find a better machine translator service.

Official human translations are super costly and not free. Usually costing a few dollars per image which is crazy. With Torii tour can do thousands of images.

I wish you would revisit Torii and maybe come talk to me if there's anything wrong with it. Have a good one.