Is it worth it to write a book with my advisor instead of focusing on journal/conference publications? Is it worth it to coauthor a book with my advisor in place of spending time publishing resrarch in journals or conferences?

Would the fact that the book is a much larger piece of work contribute more to my academic reputation? Or not as much because it won't contain as much novel research.
No, you should focus first on publishing journal papers in journals with high impact, these are the "real" things , while a book should be for later. The most important goals on any PhD would be becoming sufficient independently in order to ask questions in the field, see the connections, and publish the "played" results.