Generally, there' a tradeoff between quality vs size (mostly through energy: processing and sending more data needs more energy, which needs a bigger power source).
Presumably they also picked some reasonably available and suitable parts and tried what they can get, so there might be room for improvements now there is a baseline established.
Presumably they also picked some reasonably available and suitable parts and tried what they can get, so there might be room for improvements now there is a baseline established.