This topic is interesting even though it is a bit old. I like the ability to store my content on the blockchain, sort of like an extra data backup. But I too never have been certain, so I switched from posting on steemit first to posting on my own site first and then to steemit. Plus, you would want to post on your own site first in case the search engines decide to penalize your site's rank status, personal sites can get hurt if Google thinks you're jacking content for your site, but a massive media hub like steemit can handle it.

Post to your own blog first then here, its good practice for seo and copyright purposes.