Is there a particular reason that we should use a Map when passing in the model?

This is what Craig does in the video in Main.java

get("/ideas/:slug", (req, res) -> {
            Map<String, Object> model = new HashMap<>();
            model.put("idea", dao.findBySlug(req.params("slug")));
            return new ModelAndView(model, "idea-details.hbs");
        }, new HandlebarsTemplateEngine());

This is what I did when working on the same task

get("/ideas/:slug", (req, res) -> {
            CourseIdea idea = dao.findBySlug(req.params("slug"));
            return new ModelAndView(idea, "idea-details.hbs");
        }, new HandlebarsTemplateEngine());

So, he creates a Map and adds a single entry with the key "idea" and the value as the CourseIdea object returned by the findBySlugMethod and passes that Map object as the model.

When working on this, I just thought I should pass the CourseIdea object itself as the model and it seems to work. Now, I'm really curious to know if there's something wrong with my way of doing this. I mean, why pass a Map when we can simply pass the CourseIdea object itself as the model, since we are really interested in the details of this particular object only?

Also, I didn't need to use this.title, this.voters in the hbs template file, I could directly access the values with title, voters etc. since I passed the object itself. It looks a bit cleaner for me this way, but want to make sure I'm not missing something.

And I know we did indeed use Maps in all prior videos in the course, but haven't really thought about it until I was faced with implementing this part myself :). So it was a great learning task actually, just this little bit got me confused if I'm getting everything right.