I guess it depends on how you look at it. In the short term, yes, Steemit does have an advantage over a self-hosted site. But in the long term, if you build a community on your own site and you monetise it through affiliate marketing and your own products, could be more financially rewarding.
But yeah, for now, I'm using Steemit alongside Wordpress (not self-hosted) to get the most out of my writing. :) Wordpress is a long-term project for me, whereas I'm hoping to start getting monetarily compensated early on with Steemit. Let's see how it goes. :D I'm still a Minnow.
Thanks for sharing your views though. You do have a point. :)