JSESSIONID is used to have maintain the session between requests. Without it, you will loose the login information, the currently active cart, the checkout progress, everything. JSESSIONID is required to deliver the functionality of your store. (Feel free to consult the Servlet specification and the Tomcat documentation for in-depth information)
<baseSiteName>-cart is used to track the cart of anonymous users across visits. Let's say you browse the page and add something to the cart, without registering an account and logging in. When you return the next day, the cookie is used to load yesterday's cart so you can continue where you left off. You could disable it, but will loose this feature.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.