That footage was taken in a hurricane. Going by the BOM.gov.au sea/swell forecast charts, conditions appear relatively OK for todays search.
Last light in the general search area is at around 1230Z tonight, unfortunately coinciding with what looks like the last window of reasonable weather for some time.
Regarding the radar search...
The track spacing in poorer sea conditions has to be tighter, resulting in less area covered in the visual search. As the sea state increases, search radar like they have on the P3 must be brought down closer to the surface, resulting in decreased range and less efficient coverage.
So here's hoping they can pick up something of interest again this afternoon, pass it to a surface vessel and actually get some hard evidence.