- You don't have to pay for domains that can expire or get hijacked. Can you tell for sure whether your audience cares about whether or not you have a custom domain name? If you really do need one, it's easy to apply one to a Blogger or Tumblr account.
- You don't have to pay for hosting that's limited, private, insecure and less reliable than free public services, and you don't have to lose your data when the company goes under or fails to bill you.
- Content can be updated without specific software or hardware, from any location, by anybody who's granted access. Access rules are easy to set, and files don't have to be transferred.
- You won't look like somebody who's willing to pay for what they can get free. If it's done right, it can just look smart instead of cheap.
For me, this is about Wordpress vs. Blogger, and when to use each. Wordpress, the full installed one that everybody uses, anyway, even though it's a CMS, relies on a traditional website infrastructure to function properly. And that layer is yours to manage, whether you want to or not. If you don't need to manage that layer of things, and you're not prepared to provide the backend security and stuff to make sure all bases are covered, then don't jump into that pond. That's my advice to small business people - err on the side of small, if you're in doubt about this decision.
