I think the reason for wanting a scripting language like Lua, Python, you name it, is a simple one: not needing to run builds on changes. E.g. on a server you will probably keep compilers off the system.
Personally I prefer C++ scripting, but I have to admit scripting with Lua or Python sometimes would be a time saver.
Any way, MaNGOS comes with C++ scripting support, and if anyone desires different scripting, there are options for this, too. There are ready-made classes for Lua bindings and Python bindings available and if someone wants to see support for any of these, go fork MaNGOS and github and create your own branch for Lua, Python, you name it, and see if people like it and start using it.