There is definitely a difference between a description and a complete description, and, as another commenter pointed out, between a description and a simulation that embodies that description.

Consciousness is a property that we ascribe to ourselves and other entities. We don't experience it in others the way we experience it in ourselves, of course, but we infer it from the data available from interacting with them. They produce a pattern of signals that resonates deeply enough with us that we recognize them as like us in having goals, feelings, and access to the "human experience." For example, one of the most convincing things we could observe an AI do would be to make a novel observation about life, derived from current circumstances, that strikes us as deep and insightful, perhaps because it was hovering at the edge of our own awareness, or because it immediately activates mental patterns that we did not activate but are also meaningfully connected to the situation at hand for us.

It makes sense that if we were to copy the workings of the brain in sufficient detail in a machine, the machine would also be ascribed consciousness by human users. Perhaps we could say that it is an "artificial brain" in a literal sense, performing normal brain functions the way an artificial heart pumps blood.

In the case of the universe, it's at issue whether there is such a thing as a "complete description" of the universe, whether a simulation could be done, and then whether this simulation actually is a universe in some sense. Unlike brains, we don't regularly encounter other universes (actual, physical ones), ones which we don't live in and experience from the inside, but which we are forced to conclude are true manifestations that correspond in every important detail to our own nevertheless. A complete description of the universe by a future physicist (say) would start with a short list of all the types of information that go into describing a particular universe, like a list of type of particles and variables such as position and momentum. This list describes universes in general. Then we'd have to describe a particular universe, with a long, long, long list of all the individual particles and so on. Then we have to represent this information physically in some sort of computer, for the purpose of simulation, and perform the ongoing processing involved in running the simulation.

Finally, we must argue that the simulation is a universe. Not just deserving of being called one, or having the properties typically associated with one, but a true instance of some class that previously had the universe we live in as its single member.

One interesting feature of this line of thought is its seemingly infinite ambition. What about smaller goals we could set for mankind -- might we ever engineer an artificial star? How about an artificial galaxy? We can try to beef up the likelihood of this ever happening by considering not just mankind but any other "intelligent beings" the universe might happen to contain, in the past, present, and future. However, we are again on the shaky ground of inventing a class from a singleton. All extraterrestrial "intelligent beings" ever conceived are just stories with small, structured deviations from the human template; beings we identify with because they, too, have intentions and goals and act in their ultimate self-interest for the purpose of self-preservation and just trying to make a go of it in this big ol' universe. Some of them, it's presumed, make detailed copies of natural things at an astronomical scale and then talk about whether the old thing and the new thing are members of the same class of thing or not.

I agree that it's irrelevant to us and our operation if our brains are made of billiard balls or quantum clouds, and the same seems true of the universe.

It is still interesting whether the universe is "computable" or not, that is, whether something meeting the current definition of a computer could simulate it, even in theory. The part I object to from the OP is the implication we could draw conclusions about the origin of the universe from the prospect of being able to simulate one in theory. I think it's silly or meaningless to say we possibly -- or probably! -- live in an "artificial" universe.