Brain implants let paralyzed man write on a screen using thoughts alone

Discussed a lot about a day ago (i.e., with 528 points, 177 comments): https://news.ycombinator.com/item?id=27134049

This technology will surely help many people, especially on accidents and sensitive cases that need additional evidence and testimonies. If this will be adopted into the mainstream, I wonder how big that impact will be.