I think you mean something for audio can be used for video

?
Yes it is unusual and Tempest has a lot of restrictions in that regard, but creative devs can still find a way to squeeze out a bit of that performance. FWIW they can probably do something vaguely similar for Series X's audio if they wanted to get creative enough, the the specific degree of types of non-audio graphics-type tasks would likely vary since they aren't repurposing a CU core the way Sony is.
I base this on the fact a game actually did do this, Shining Force III on the Saturn, over two decades ago. They used the Saturn's Yamaha audio DSP for some graphics and logic work when able. I should try finding more information on that but it was really cool to find out devs went to such lengths to work within the design of such a system.
The better question is will any dev utilize Tempest (and to somewhat lesser extent, Series X audio core) for non-audio tasks? I don't think we'll see anything like that until well into the generation, and we have to keep in mind we're only talking about a "few" hundred GFLOPs at most with either. It seems like a lot in isolation but it really isn't when compared to the capabilities of their GPUs. Still though, anything that can be squeezed out for extra performance, even if you have to get a bit creative with it, is ultimately good to have.
Or we can take them at their word and I believe most people knew it was referring to FP16. But that only really means it would likely scale WRT FP32 of One X CPU cluster, if anything. FWIW Sony didn't specify FP16 or FP32 when comparing Tempest to PS4 CPU.