Underscores in HAL

I just realized I like to use underscores and just came across this in the manual: linuxcnc.org/docs/html/hal/general-ref.html

HAL components should not use underscores or “MixedCase”.

How critical is it? Docs talk about tree structure.Does it just affect how it gets organized?

Underscores in C become hyphens in Hal pin names. So I think its best NOT to use underscores. All my pin names in my components are lower case with hyphens.

Thanks rodw, that makes sense.