>>5756765The mental art skills - visualizing, visual memory, construction, composition, etc - all translate between all mediums seamlessly.
The practical skills, line weight, rendering etc don't. If you're doing work in digital, you might get used to being able to get actually black darks. Good luck getting them with graphite. You might be used to shading large areas in perfectly even tones, good luck with that in graphite/gouache/whatever. You might get used to infinite layering, and good luck with that on any /trad/ medium - even acrylics and oils change the surface if you have a lot of layers. You might be used to undoing something, and good luck with that with watercolours/inks.
Of course, in reality the latter is easy to learn and the former is what really takes time with art. You will feel super fucking clumsy in /trad/ at first, but it's mostly a hiccup of few weeks to a month at worst.