When you are writing a spoken word poem, the tools you're working with are your voice, your body, how it's going to sound to someone when you're saying it out loud. Which is different from when you're writing it on the page. That toolbox becomes how does this look visually on the page, how does this read among pages, how is this in relation to poems that are before it or after it. I don't think one is better or more successful than the other. You've just gotta think about "what are the tools I'm using, and how are they most effective in this form?"