Reading this I see for the first time why the notion that the universe is a simulation isn't so far fetched.
I have to disagree and I can not really understand what is so appealing about the simulation idea to many. It is an idea that will lead nowhere because you are unable to distinguish a real universe from a simulated one. In order to do this you would have to know what at least one of those scenarios looks like and then compare the universe you observe to what you know to be true about a real or simulated universe. It…
The reason is that we can safely assume that we are within one of n + 1 realities. The n simulated realities and the 1 real reality. Unless you attribute some sort of exceptionalism bordering on creationism to our existence, there's every reason to think that n is going to proportional to the number of advanced civilizations in existence and is presumably going to be very very large. And as you increase n the odds of us actually being in the 'real' reality, which are of course just 1/(n+1), approach 0.
Like you mention it's something that doesn't necessarily go anywhere. Even if you "prove" it after death, that life you'd be experiencing at that point faces the same logical issue - at least unless the argument loses consistency at some point. Something most seem reluctant to admit is that it's also comforting as an atheist. I always expected the infinity of time after my existence to be very much akin to the infinity of time before my existence. That's just disappointing. The seemingly high probability that all is not as it seems is certainly emotionally appealing. But it's certainly not just the emotional appeal driving me there - I could obviously have chosen to invoke Pascal's Wager in the decades of time prior to considering this, but it seemed fake -- this, somehow, does not.
It also answers, or at least compellingly kicks the can, of the question of existence. If I write a program to spit out a random number, I presume that there is no entity that suddenly whisks into existence under the false impression that it is choosing a random number - which it then decides upon, before then being whisked out of existence. So why am I, the 'thing' spectating the outcome of the series of chemical and electrical reactions carried out by this body, here? Descartes would have quite the time if the answer to our little question had been yes during his time. It changes the picture so much more than the dreams that drove his ponderances.
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From a scientific point of view, it's obviously not a great concept as it cannot be falsified. And like you mention, it also cannot really be physically proven without begging the question. On the other hand, it can be treated as a soft science and if a preponderance of evidence does lean towards supporting it then we can at least say, "Hmm.. well we can't really say anything for certain, but that's certainly interesting."