> what experiments it would do within that space are hard for us to imagine

The only thing you could do in a "digital space" (a.k.a. on a computer) is a simulation. Simulations are extremely useful and help significantly with designing and choosing experiments, but they cannot _replace_ real experiments.

> Like, the time window from the discovery of fire to the discoveries of Quantum Mechanics but in a flash.

And my point is that there's no good reason to think this is possible and many to think it isn't.

> it's more of a fun sci-fi idea

It's being presented as extremely serious possibility by people who stand to gain a _lot_ of money if other people think it's serious... that's the point of the linked post. Unfortunately, these AI boosters make it very difficult to discuss these ideas, even in a fun sci-fi way, without aggravating the social harms those people are causing.