Rean and Zangeshu didn't really see the absolute necessity of having to communicate with the device with the tendrils. The idea of having those things spreading through your brain truly didn't excite them. However, it was understandable. Through that method, a direct connection between the soul and the brain to the device was possible in real time.
However, neither Rean nor anyone else there liked the idea of having those tendrils spreading through their brains. So, the idea they came up with to avoid that was a bridge.
How that worked? It wasn't much different from the communication badges Rean created back in Lisan Universe. There, everyone sent their own Divine Senses inside and controlled the CD's options as if looking at a Virtual World.