ReSharper Ultimate is a license that combines all individual JetBrains .NET tools, as well as ReSharper C++. Each ReSharper Ultimate license allows a single developer to use ReSharper, ReSharper C++, dotCover, dotTrace and dotMemory. If a single developer uses Visual Studio to code both in C# (or VB.NET, or TypeScript, or other languages supported by mainline ReSharper) and in C++, they would probably want to have ReSharper help them out in both worlds. Purchasing ReSharper and ReSharper C++ for this developer is a valid option but buying ReSharper Ultimate will actually cost you less than the two-license combo and will additionally make the developer eligible to use dotCover, dotTrace and dotMemory.