It's just a thought experiment to try to see what your ethical and ontological commitments are. Think of it another way; if you could push a button and everyone would instantly be in Nirvana; no effort needed and no questions asked; would you do it? You might say that would have to be a fake, unearned Nirvana, but could there be any difference between absolutely believing you were in Nirvana and actually being in Nirvana? If so, what could the difference be?
Ok, I find it interesting in that it is like holding up a mirror to yourself, that you, or someone else, can view your ethical and ontological commitments objectively.
These are my initial thoughts;
That if I did press the button. The people, myself included, would not be themselves anymore, indeed they would be so removed from
themselves, that the thought experiment becomes meaningless. This is why in mysticism (as I see it) the soul develops from , I, to , I am, to, I am that, to the point where it realises, I am that I am. In the final level of development the being would remain the same being when the button is pressed. Prior to "I am that I am", the being would loose their personal identity in the switch. in this prior state beings are formed, held up, propped up by tangible realities in this world as they are, take this away and they (their being) collapse, disappear. If they(their being) are thrust into "I am that I am", again they would be in a fractured, or collapsed state.
Secondly the idea of being in a vat and not knowing it is incoherent as we don't know if we aren't already in that state, that there is any other possibility to this state etc. I know that this is not the point of the experiment. But it does illuminate the issue which you may be enquiring into of the ontological basis of our reality. The implication being that if the button is pressed the beings will be in an exalted state, but it would be in some way false, a a lie, a fabrication. There are two problems with this, firstly as I say, we might already be in that state, life might not be possible without it being fabricated in some way. Secondly if the button were pressed the fact of there being a brain in a vat might become meaningless irrelevant, because we are phenomelogically our being and our experiences and the vat is simply an inconsequential artefact of material processes etc., or might simply disappear.
Third, the ways in which our current way of life would change. Provided there is no vital purpose being served in our living this way of life, then whilst bearing the first two thoughts in mind, I would have no problem with pressing the button. However if there is a vital purpose in us living this life, then I might in pressing the button, pass the buck and that purpose would have to be carried out by some other unsuspecting bunch of beings at a later time. So I would be bottling on my purpose.
Fourth, We might be here performing a service for some other lives, or purpose. What about for example the other animals and plants we share our lives with, or the planet, or the material of this universe? We might be fulfilling a vital custodial role within the wider system and so fulfilling our personal desires and wants in an instant might be a cowardly act of refusal to perform our natural role in nature, a role we might have actually chosen, or offered to perform. In this light, the thought experiment comes across as a conceited flight of fancy.