Do I need to study C++ in order to use SteamWorks?
In theory, using the Engine’s OnlineSubsystem(Steam/Live/Playstation ect) should negate the need for SteamWorks as the Game should work on all online platforms while using the same function calls from OnlineSubsystem. However, I do believe some of the SteamWorks functionality (Getting the avatar) isn’t implemented in the current Engine version yet.
However, I would recommend learning C++ if you are hoping to integrate your system with specific online platforms.