I live outside of the US for most of the year and can say that my driver's license is not at all useless as an ID.

In fact, I have been at police checkpoints in two countries where they refused to see my passport and specifically requested that I present my driver's license - but these were both when I was driving, of course.

An Australian one is fine in the UK, you can even drive using one.

They will actually sometimes accept them here in Vietnam for various things but Vietnam is still kind of the wild west legally. Certainly not a good idea to count on it.