WordPress.com should not be mistaken for WordPress.org. The .com domain is a blog hosting provider, and while you can host your WordPress blog on the site, there are a number of limitations you should be aware of. WordPress.com does make use of WordPress, but it does not allow you to install any plugins on your site. Many WordPress sites, especially those that do eCommerce, heavily rely on these plugins. Without this function, the blogs hosted on WordPress.com are very limited and are only able to provide basic functions.
A number of users new to WordPress assume that the .com domain is a part of the official WordPress package and pay for server space. However, as they learn more about WordPress and its functionality, many switch to other hosting options that do not limit what they can do with their WordPress website.
Another limitation WordPress.com imposes on the sites it hosts is that users cannot install and use custom themes. This is another major reason many people choose WordPress over other CMS software. Monetization and SEO limits have also driven users away from WordPress.com. The site does not allow users to use Google Adsense or other ad platforms.