Not true: You ideally still need as many electrodes as feasibly possible for a more complete BCI interface, implanted or not, regardless of the resolution (constant bitrate) of the electrodes. It is true though that certain implanted electrodes have higher resolution than transitional EEG caps. But at this point, it is not that big of a deal because neurosurgeons can only implant a very limited amount of electrodes. Even if they could implant 256 electrodes, the processing of this would be extremely limited. Even a standard 19 channel EEG cap can require a top-of-the-line computer (think i9 processor, 64 GB RAM, or better) for some use cases, due to latency issues involved especially with the amount of signals being used.
Also: With EEG caps, we have filters that remove the noise from movement and muscle activity very well.
Also: With EEG caps, we have filters that remove the noise from movement and muscle activity very well.