Why should you go with WooPress?If you can't afford to buy web hosting or domain, or you are a newbie trying to learn wordpress or how to write great content with wordpress then WooPress is exactly what you need.
This Forum on wordpress.com shows the disadvantages of WordPress.com along with the advantages of a self hosted WordPress, but I am not going to talk about self hosted WordPress here, as we are talking about WooPress which is itself a self hosted WordPress site and supports everything a self hosted WordPress should. And if you want to more info about the difference between a self hosted and hosted WordPress you can go with com vs org article.
WooPress comes with all the necessary plugins preinstalled, so you don't have to worry about your website traffic, email lists, SEO etc. You just focus on content as they have everything else for you. Write great content on your free blog with WooPress, an alternative to wordpress.com, and attract more readers. The most important thing in WooPress is you can set your blog or blog posts to a private or public mode.
Why should you not go with WooPress?If you can buy a Web Hosting or register a domain, and you are an experienced content writer or you have experience with wordpress then you should not go with WooPress.
WooPress is running WordPress itself but providing free blogs to everyone with some premium features like no ads, good & necessary preinstalled plugins like SEO, Google Analytics, Mailchimp and more.
The main drawback I think about WooPress is that there is no theme or plugin editor provided, you have no option to add or delete a plugin. Even you can't upload or delete themes and you don't need to because WooPress provides about 125 preinstalled wordpress themes and all necessary plugins for your free blog.