What kind of evidence are you hoping for? Say we measure particle trajectories very precisely and discover something that looks a lot like floating point rounding errors. Now what? How would you know that the physics of the real universe doesn't resembles floating point numbers? It is absolutely unjustified to jump from the universe looks smooth to us but our computer simulations have finite precision to the real universe is smooth and simulated universes might have finite precision.

It is an attempt to distinguish something we don't know from something else we don't know. Everything we know about our universe might be something that applies to real universes or something that applies to simulated universes depending on whether we live in a real universe or in a simulated universe. Even worse, we know nothing at all about simulated universes if we live in a real universe and we know nothing at all about real universes if we live in a simulated universe.