WordPress.com takes care for your security such as site hacks or comment spam. It is a multi-connected network so there are chances for other site owners to visit each other and converse.
If you have a site on WordPress.org then you will be responsible for all forms of maintenance and security of your site. As a website administrator you need to keep monitoring the activities of your website.
Is your WordPress flexible?
WordPress.com is very restrictive and not very flexible. You can use any custom theme templates, do any e-commerce business or use any plugins built outside the website. You can never get FTP access to your files.
In case of WordPress.org you control over everything regarding your site. You can upload custom theme templates, third-party plugins, conduct business transactions and more.
There is no limit or rules to follow because you not under the rules and regulations of WordPress.com. You are your own boss.
Which WordPress platform can expand your business?
Affiliate marketing is monitored and strictly forbidden in WordPress.com. If you are looking forward to sell a product with any type of check out system, you can’t use WordPress.com.
WordPress.org is the real choice for serious writers or business. You must use a self hosted WordPress.org website if you want to custom your website or intend to grow your business through it.
If cost is everything to you and just require a simple place managed for you on the web without caring the restrictions and regulations, then WordPress.com is the perfect fit. It is great for hobbies or special interests.
Hope things are cleared up that can help you make the right decision!!