Or is engrave more planned to build blogs for the world instead of steem user?
I don't want to speak for @bgornicki, but I think this is much more ambition approach, to focus on creating best user expirience for not-yet-Steemians.
I think that Engrave for many users can be really easy way to be introduced to Steem blockchain without a need of asking of too many questions about how this works.
If you will simply read your favorite author on my-blog-about-games.com after a while you will notice that you can do a little bit more if you will be logged with this "weird Steem cryptocurrency thing".
With Engrave you can actually do with your blog whatever you want. If you want to add Google Analytics and actually know what your fans actually read - you can do that. If you would like to add a widget to your website, you can do that by a custom template. Engrave is prepared for non-technical users, but at the same time, technical users can adjust it in all possible ways.
Why should I use engrave > steempeak if I want to blog for steemit user and not for the world?
For such users, there there is a little bit less arguments. But for instance, with Engrave you can create categories, so one section of your blog can be about games and another can be about new phones :)