I think the video was put out to put RB at ease.
So many people saw that video and instantly said it looks just like RB (going by comments I've seen on FB, youtube, etc.)
So if they think it is RB, what do the cops do? Not say anything? Say they suspect RB? Or... play stupid and ask the public if they know anyone that walks like this, please let them know? Meanwhile, it's pretty obvious that RB does walk like that (even if he's not the killer).
Doesn't RB realize that he does walk similar to the killer? Isn't he wondering why they haven't named him as a suspect or acted like they think he's a POI? Or is he just that full of himself that he thinks he really fooled 'em? LOL
The narcissistic person would probably think, "Omg, the cops don't even know that's me in the video! How stupid they are!" So he gets comfortable and maybe slips up later?
All above is my opinion only!