Side by side
- Cost: .org software is free; you pay a host of your choice. .com has a free plan with ads and a wordpress.com address, then paid plans; installing your own plugins and themes requires the business-level plans.
- Control: .org lets you install anything and edit any file. .com restricts plugins and code on the lower plans and does not allow some things at all.
- Maintenance: on .org you (or your developer) handle updates, backups and security, or your host does. On .com the company handles the platform and you handle the content.
- Portability: both let you export your content, and a .com site can be moved to a self-hosted install. The reverse is also possible.
- Ecommerce: .org with WooCommerce is the standard. .com supports WooCommerce only on its higher plans.
Which one should a business use?
For a business website built by a developer, self-hosted WordPress (.org) on good managed hosting is the normal choice: full flexibility, you own the hosting account, and the cost is similar to or lower than a comparable WordPress.com plan. WordPress.com makes sense for a personal blog or a very small site you will run entirely yourself and never want to think about hosting for.
Either way, the dashboard looks nearly the same and your content moves between them, so the choice is about control and cost, not a one-way door. Is WordPress free breaks down what you actually pay for.