Why not use C++?

C++ does offer a little more control since the developer is in charge of memory management and there is no garbage collector. For this same reason, C++ will have slightly better performance. In some cases, Go can actually outperform C++.

C++ is very mature and has a large set of third-party libraries. Libraries are not always cross-platform and can have complex makefiles. Cross-compiling is much simpler in Go and can be done with the Go toolchain.

Go compiles with more efficiency because it has better dependency management. C++ can re-include the same header file multiple times and cause compilation times to balloon. The package system is more consistent and standardized in Go. Threads and concurrency are native to Go and require platform-specific libraries in C++.

The maturity of C++ has also led to the language growing and becoming more complicated over time. Go is a refreshing change with a simple-yet-modern language. C++ is not as friendly to beginners as Go.