What is the tl;dr of the tool? How does it differ from the description of its category, IDE?
Xcode is a native programming tool developed for macOS. Its primary intended use is development of iOS, macOS, tvOS, and watchOS applications, but it includes compilers for C and C++.
Why use this tool over an alternative?
To develop for the Apple ecosystem, Xcode is a necessity. XCode is the only tool that can compile runtimes for iOS, macOS, tvOS, and watchOS.