Practicing with simple values leaves space to the work on details and a more emotional and strong impact.
We have just the grayscale as a tool and we need and can create a powerful illustration out of it, even if it's 'just a sketch' it could be strong enough. Also we have the possibilities to study and see values in a clearer way, to use shadows and light to convey very different feelings and moods to the subject itself and we don't have to deal with colours so we can proceed without further difficulties.
Personally, I like to use B/W and leave it as it is for the final artwork, it's useful and relaxing.
It's my first blog post here, don't know if it fits the 'standard', but I wanted to try!
Thanks for reading.