A book is maybe about 350 pages, and the prose allows for...

A book is maybe about 350 pages, and the prose allows for readers to get a glimpse into the internal lives of the characters. A screenplay is 120 pages, and it's all dialogue and action. The pacing of films is different, the structure is often different, and the internal lives of the characters must come across through the acting. Movies are just a different experience than reading - so it just depends on what an individual prefers.