Actually it really depend on the site owner, if the site owner don't care anything and allow registered user to publish or feature any blog post he want from his website, then your point should be accepted.
But most of the cases, if the site owner allow to do that, it might be causing a lot of spammer come to his site and publish or feature any spam post from his website, because most of the spammer will target this kind of website which do not have any restriction for this, so they can easier to share some advertisement on their blog post then feature it, once those spammer post featured, so it will show on the blog listing page showcase area, if those spammer blog post contain some of the indecent photo or content, it will affect with his website image.
So it will be better make it only allow site owner or moderator can able to do this feature post action.
By the way, if you really want this feature, I would suggest you start a new thread on our forum then select " Easyblog - feature request" category, so we will see if a lot of user request this, we will consider to add this in the future.