But what if, against the odds, we actually happen to live in the true base reality, and indistinguishable simulations of reality don't exist, at least not yet? Wouldn't believing in a simulation be a mistake then?
Yes, anyone who believed this reality was a simulation would be wrong in that case, but so what?
Firstly, the belief of those who think they live in a simulation about the sanctity of life and the goodness of being present in the reality they experience, as well as allowing everyone to freely seek and pursue their own purpose, would still be all good and right.
If someone mistakenly believes they live in a simulation and, because of this, is kind to themselves and others, that isn't wrong, now is it?
Secondly, a simulation indistinguishable from reality and true reality differ for those living in them only in that death in base reality is really the end of the line, whereas in a simulation, one returns to the underlying reality.
If someone believes they live in a simulation and gains comfort from the belief that they would meet their deceased loved ones again after returning to a lower reality, or that they could return to this reality again later, they still won't be disappointed when they die in base reality, as they cease to exist and experience nothing more.
But there is another difference between a simulation and base reality, in that while the former was created for a purpose, the latter has no purpose - it just is. In base reality, we only have the purpose we create for ourselves.
Believing in a simulation might, with a small probability, be wrong, but it does no harm. Instead, it allows one the possibility of believing in something greater than oneself, albeit eternally here unknown, which can help each of us find our own significance - if nothing else, we can always serve reality, peace, and freedom, and the grand exploration we are experiencing together as conscious beings in this reality.