Is the command name character restriction necessary?

[MCStreetguy]

I recently set up a command line application with this library and I'm very impressed about it.
The possibilities totally fulfill what I tried to achieve.

But now I stumbled upon a restriction in the command names.
I wanted to create "namespaced" commands, just as e.g. the Flow Framework does.
I tried to register core:cache:flush but I receive an Exception, telling me that only word characters and hyphens could be used as name.

Is there any reasonable cause for this restriction?
Would it be possible to add more chars to the pattern or even leave the naming completely up to the developer?