where is my SBD???

Well, i wanted to promote a post, but since I did not have 1 SBD, I put 0.5 SDB and it was rejected.

When looking at my wallet my 0.5 SDB was transferred to @null

From which I got this info: https://steemit.com/steemit/@steemitblog/introducing-promoted-content

Now my question is, to put values ​​smaller than 1SDB this is lost?