image ready vs. dreamweaver



i am in the beginning stages of web design. I've found that creating the entire page in photoshop, bringing it to imageready for the rollovers and then opening it in dreamweaver works fine. What are the limitations to this? Why bother creating the page in dreamweaver? (actually deciding what goes where) instead of photoshop? Am i headed for problems down the road? any advice would be helpful. thanks.