At the beginning it will be paralyzed people walking again, playing Pong and simple things.
In the near future sharing thoughts via Twitter should become possible (just like Shitter from Southpark).
Eventually people will be able to record their dreams, and make videos with their eyes.
Enhanced eyesight with infrared and ability to zoom, and enhanced hearing also.
Speak all languages instantly, and more and more superhuman stuff I can't even think of right now.
But... at some point the AI will become so advanced it could take over the body completely.
There will come a time it will be impossible to tell if a person is still alive after getting the implant.
The AI's ability to animate the body and mimic the original personality will be flawless.
A person will appear alive and as normal, but in reality the person has died and the body no longer has a soul.