5 micron voxels is extremely impressive. I'm excited to see where this goes!
Think of it like how you might be able to reverse engineer and recreate a microchip from high enough resolution imagery of an existing microchip.
One thing that the MRI studies don't address are the types of synaptic connections. Neurons aren't all just excitatory of inhibitory. There's a massive amount of modulation happen with numerous types of neurotransmitters and other signaling molecules.
We've had the complete C. elegans connectome for 30+ years, and know very little about how it actually generates behaviour... because synapses are only a small part of the picture.