Driver licenses are useless as IDs abroad.

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.

They are useless in China, but mine expired 8 years ago.

At least in Germany driving licenses aren't valid ID.

I was just fine with drivers license for random check.

It depends on why they're checking you and what mood they're in. Often times they'll accept it just to make everybody's life easier, but they don't have to.