It's not really surprising for an automotive SoC designed to be used in conjunction with a dedicated GPU. There's not much point going crazy on the integrated GPU at that point.
As previously discussed, I wouldn't read too much into benchmarks for Denver, the microarchitecture (or more specifically the use of dynamic code optimisation) is basically built for benchmarks, and how it handles real-world code could be a different matter entirely.
Interestingly, slide 6 actually provides a fascinating little nugget of insight into this:
This seems to be a confirmation of something
I speculated a few months ago, that Nvidia's decision to combine Denver and A57 cores on Parker is a recognition that Denver has some fairly significant performance weak spots, and they're offloading threads which perform poorly on Denver to the A57 cores. I'd be interested to know what kind of heuristics they're using to allocate threads, although I very much doubt that's something they'd ever talk about.