I'm not using Creo Elements/Modeling PE, but rather Creo Parametric. It saves STL files in whatever units the model is created in and there's no option at the output to change it.
The process to change units is probably about 12 or more clicks and then when I'm done exporting, I have to do it all over again to revert back to inches.
Doing the conversion in Cura is certainly shorter, but sometimes the models come in and are too small to see.