Trek-science has always been fun and this new take on it is no different for me. but quantum physics is that weird science that says anything can happen for no reason whatsoever :P Tomorrow we might learn that there is a type of mushroom that curiously has root systems that are influenced by some kind of weird quantum entanglement effect. So today we have a made-up living organism that exists in our dimension but is entangled with the made-up realm we learned to accept, allowing for even faster than FTL drives possible. Nowadays we accept that it might be possible, but the engineering and power to do so is outside our current grasp. The spore drive concept is stupid and unrealistic, because while wormholes and warp drives at least fleetingly touch base with reality (as in: Its theoretically possible in physics) the spore drive completely ignores that quantum effects don’t exist above the Planck scale. The made-up realm of subspace allowed us to believe that FTL drives were possible, at a time when we were told that FTL is absolutely without-a-doubt impossible. Now, we get more sciencey sounding explanations, but they're still the same magic. The Traveler has never been a completely believable character through scrutiny, but he was the type of 'evolved' alien that we were use to back in the day. Book, having committed some light but mostly understandable treason is sentenced to. An idea that regular everyday beings can, in fact, evolve to a 'higher plane of existence' that sci-fi loves to posit. The 10-C uses their final DMA-caused wormhole to transport them all back. It also retroactively makes characters like The Traveler more believable, in that we can kinda say there is precedent for organic beings to be tied into subspace purely by genetic makeup. It was so much fun to hear Stamets talking about it. The technobabble explanation of it in episode 5 (or was it episode 4?), well I totally geek out with technobabble in general, but it made sense in-universe building off already established Trek-science ideas. Star Trek Discovery’s spore drive opens up a new possible mechanism for faster-than-light travel that may be even superior to warp drive. I really enjoy the idea of living and corporeal fungus has part of its structure entangled with the quantum realm that its root system can reach into the depths of subspace.

The mycelial network and the spore drive seem like a natural progression of the same idea, but it has the added fun of an organic component. When I was a kid, I thought subspace was a real thing and that the science of pushing a ship into the subspace plane with a warp core was totally believable. Personally, I think the mycelial network is a fun take on the same silly Trek-science of subspace.

Spore drive in action