This is a fundamental philosophical question. The same question can be asked about more traditional physical models, e.g. what is Einstein's spacetime composed

This is a fundamental philosophical question. The same question can be asked about more traditional physical models, e.g. what is Einstein's spacetime composed of, and how did his equations of general relativity come to be? Are they real, or are they just a model that we use to describe reality? Over time, physicists have come to take models very seriously (thanks in part to Einstein's 1905 papers). That is, when our model says that electrons act like particles and waves, we assume that electrons really are these odd things that are somewhere in between a particle and a wave. So, if it turns out that Wolfram's ideas have merit, and there really is an underlying spacetime network which can be used to model and derive all of the known equations of physics (and likely some unknown equations), then at that point we would have to take very seriously the existence of such a network. We would be forced to think of a seemingly continuous spacetime as a special facet or feature of this underlying network, in the same way that we now think of space as a special feature of the more general spacetime.