Why use Go as a scripting language? Why not? Go is relatively easy to learn, not too verbose and there is a huge ecosystem of libraries which can be reused to avoid writing all the code from scratch.
Some other potential advantages it might bring:
There were previous attempts to make Go scriptable using a shebang line, however (mostly because lines starting with # are not valid in Go) the solution is not perfect: you end up with .go files either to be used as scripts only or as real compilable Go programs, but not both. Ignat describes a way how one can use some advanced features of binary execution on Linux to overcome previous problems and make Go truly native scripting language.