Because someone who understood the available resources and the actual user needs performed an analysis and determined that this would be sufficient. Commodity hardware eliminates the need to spend a year or two engineering a custom board, dealing with vendor BSPs, etc. It also eliminates the FTE that would be required to support all this.
They could also have chosen to use a reference design from another manufacturer but it's basically like using RPi but 100x more expensive. There's a good case to be made that this is the most cost-effective design for what they're trying to accomplish.
They could also have chosen to use a reference design from another manufacturer but it's basically like using RPi but 100x more expensive. There's a good case to be made that this is the most cost-effective design for what they're trying to accomplish.