One question that students often ask me is why they need to learn drawing when they want to paint. The main reason for this is that black-and-white drawing will teach you most of what you need to learn about painting - form and direction, light and shade, perspective, positive and negative space, foreshortening, composition, anatomy, character, texture and detail. It will give you hand control and eye-hand coordination. It will also give you observation practise and critical evaluation skills, which further teaches you how to see and correct your own mistakes.
And it will do all of this without colour (hue). That is an advantage in that colour has its own complex rules, so that is one less thing to worry about. But in the overall scheme of a painting, colour is a small part of believability. When trying to convince your audience that your subject matter is real, getting the form right (through tone, direction, perspective etc) far outweighs the importance of getting the colour right. Colour changes rapidly and often, through movement, light, shadow or the presence of other objects. We recognise the object through all of these changes because the form stays the same. If we convey the form believably, we have our audience.
In fact, colour can distract us away from form. It can dilute the all-important tones and tonal changes that create the illusion of form. We can get so caught up in trying to make a vase a beautiful orange that we forget to make it round, shaded, highlighted, full, heavy and reflective. Learning to convey these subject qualities without colour means that you learn their importance and the skills required to achieve them. Colour can then be added to into a working system, taking its place as one quality within many.