a) Doing so signals that you'd like commentary on your work. So it is a step toward promoting the open exchange of ideas.
b) Functionally, it is actually easier for others to be notified that you've created new work that they might be interested in.
c) Outsiders to the class can become aware of what you are up to and if they are interested in it might participate themsevles.
d) Because of (a) - (c) there is potentially a performance effect on what you produce. In other words, your apt to put in more effort to make your work appear well done, if it is publicly available.
e) You have an archive of all your work after the course concludes.
Those are all good reasons. However, owing to government regulation about student privacy, notably FERPA, you have the right to keep your identity in the class private to those outside the course. So if privacy is a concern of yours you can take a modest step of identifying yourself by first name and last initial. If you want more privacy than that, I can make a site in Compass for you where you can do your course work.
The approach we'll take is that you opt into having a blog, in which case you send me the url for that and then I'll include it in the Student Blogs section on the course site, or notify me that you want a space within Compass instead.