I could totally see some parallels between this and a real life Experience Machine. Although this is more about pure sensations rather than simulated experiences.
Is the issue that the pleasure coming from isn't real? You could argue that the pleasure coming from drugs (including alcohol and tobacco) aren't real, which I think is what you were getting at.
So it's probably something else.
I think the difference comes from the separation from consuming a drug and then feeling happy in your brain versus zapping your brain into a happy state.
That said, if it works, I think it's something I'd buy.
Right now it's at a combination of price and lack of convincing evidence that I'm hesitating, but if it were found to be totally proven or at least reasonably so and a bit cheaper I'd totally give it a shot.