Just wondering what your preference is? Fo you perfer black and white sketching/shadong or coloured pencils to shade and colour after the line work? I personally like sketching but I ocaisionally like colour. It depends on the picture for me
I enjoy sketching, I do a lot of it, but I find it does not produce great finished images. And I don't count in depth graphite renders as sketching.
A sketch is an idea, something that has to be transformed into something final either by adding colour or tracing and reworking it with more detail and depth and yet keeping the life of the sketch.
I like to try to transfer the energy of the sketch to the final image. One thing I hate is losing that freedom and flow a sketch has by making the final too stuffy.
I have actually seen myself scanning my sketch and just cleaning that up, getting rid of all unwanted marks and just using that sketch instead of lining over the top. It depends, but yes, the energy is important, esp for comic work where you want the characters to seem alive like they're moving or talking etc.