That is my point.
I imagine that, if this was a possibility, quite a lot of people would be ok (or even demand it) to make available "150 years after natural death" sentences, so that they can apply it to their newly deposed dictator. Then, once the new rulers become entrenched in power and begin to like it, they can start using it on their political opponents. Prisoner exchanges between warring countries could become quite interesting. Quite likely, some people might feel inclined to hang on to their loved ones forever. Remember Terri Schiavo [1]?
Feel free to imagine more interesting scenarios. If you don't start to shudder, you're just not thinking big enough. You can watch this Black Mirror episode [2] to get you started.
This gives a whole new meaning to the expression "killer application".
And the technology is here, it's only a matter of time before this kind of abuse starts happening.
I'm not saying we should not continue researching this, as the possibilities are endless, but let's not put the pitfalls under the rug
(This is a relevant YouTube video to the discussion, not spam.)
So it can easily be made to feel pain -- just pass in the same signals the nerves would have.
Also, people who become blind later in life often describe it as "black", so I think it's reasonable to assume that's how the brain would interpret lack of sense.
(If they're explicitly trying to cause me pain, that would be a no.)