Specify enex files and output directory on the command line

Is there a reason the input and output files are specified in the json config instead of the command line?

I'm trying to convert a tree of directories and I'd like to keep the directory structure. This would usually be very easy to script as most command line tools would use arguments like this:

> yarle --config ../config.json --output-dir /foo/ *.enex

This allowing me to run that command in multiple directories to convert all the notebooks present.

If this is possible please can we document it in the readme?