I mean hiring page doesn't mean they actually use it in the product. You can use ROS for designing the system, but in terms of performance it has issues if you try to use it in an embedded context. I still kind of doubt they have it running in their product.
Makeshift solutions last the longest, I'd highly doubt that they run 2 messaging systems side by side, thats just unrealistic for a startup. Especially considering that ROS is very invasive with it's MSG format and build tooling.
