My concern, however, is this: In a simulation there is no real harm done and a simulation can always be repeated. This is why we use them for practice: they simulate something real without the same absolute and irreversible consequences (think of flight simulators for pilots). However, we are taught that we shall all be judged for what we have done in this life for all of eternity. Now that would be unfair, to say the least, if it were but a simulation, as no “real” harm could have been done to anyone or anything in this life. But we believe that sins against God and neighbour are real, just as charity is real: both have their deserved deserts, be it praise or blame.
A reality once removed is a video game or simulation; it is still not reality and the same rules do not, at the end of the day, actually apply - exactly because it isn’t actually real. Hence my concern about theories that divorce us from this reality in any way is that they ultimately undermine morality. The “rules” and “morals” of life and healthy society are normally difficult, challenging and demand sacrifices from us; and they are hardly justifiable and defensible in a mere simulation, considering their costs, usually pleasure or comfort or indulgence or whatever and hardship instead.
For the atheist, a reality that isn’t actually real with no ultimate or final end or destiny makes the sacrifices necessary for moral living rather more difficult, if not actually impossible, to rationalize. After all, what fault is there in harming a hologram?