For beginning bloggers, this could be a problem. Especially since a domain + hosting + self-hosted WordPress is like first step to success, and considering that you are unsure whether the site will last through or not... Is it really worth those minimal investments? Or is Bloggers/WordPress.com/.co.cc or a free subdomain with a free host the way to go, while losing the brand?
Of course it's worth the minimal investments to get your own domain/hosting..even for beginners. You never know, the blog could explode. You don't want an exploded blog hosted on a subdomain and free hosting, now do you? :]