Procfile and procfile.dev useful if not using Heroku?

Newbie in Ruby on Rails. 
I noticed that we have procfile and procfile.dev: are they relevant if not using Heroku?

I'm not the ultimate expert :) but it feels like procfile is a heroku concept to execute commands but outside their context of heroku, do not have a use.
Yet, when I look at procfile.dev, it seems it participates in the building with yarn of css and js, so eems useful even without heroku.

Could not find guidance about this on official Docs. 

Thanks,