The use of TcpClient and TcpListener just means a few less lines of code. As you say it’s just a wrapper over the Socket class so there is no performance difference between them it’s purely a style choice.
Update: Since this answer was posted the .Net source code has become available. It does indeed show that TcpClient is a very light wrapper over the Socket class which is itself a wrapper on top of the native WinSock2 API*.
- On Windows. Will be different for .Net Standard/Core etc. on other platforms.