Cinebench/4D does have "hand-optimized" ARM instructions. It would be a disaster for the actual product if it didn't. That's what makes it interesting as a benchmark: that there's a real commercial product behind it and a company interested in making it as efficient as possible for all customer CPUs, not just benchmarking purposes.
Albeit for later releases this is less true since most customers have switched to GPUs...
Cinebench/4D does have "hand-optimized" ARM instructions.
It doesn't. As far as I know, everything is translated from x86 to ARM instructions - not direct ARM optimization.
Cinema4D is a niche software within a niche. Even Cinema4D users don't typically use CPU renderer. They use the GPU renderer.
The reason Cinebench became so popular is because AMD and Intel promote it heavily in their marketing to get nerds to buy high core count CPUs that they don't need.
Albeit for later releases this is less true since most customers have switched to GPUs...