You do the best work when you are interested in what you are doing. Working without genuine interest is a waste of time. Your writing may take the form of an actual screenplay. It's a very simple, straightforward and natural way to express filmic ideas. This means that a reader skims through the material, reading only the spoken words, not the description.
Dialogue is fast and can keep a story moving.
Of course, many stories are more action-dependent and have very little dialogue. Also, dialogue may simply be functional, and not particularly eloquent. Functional dialogue is in fact, more condusive to filmmaking in general. If you feel comfortable sketching or doodling, don't hesitate to draw the ideas from your mind. Drawing is another direct way to further shape your ideas on paper.