Integrating an accelerator into a dishwasher is also expensive. How many inferences are you going to get out of it before the hardware is outdated? Once a day for 5 years may not be enough to justify the cost. Compare that to having a single GPU in a server in your house that services all your IoT devices, which can be readily upgraded and requires no special software. The is no benefit to doing inference on device unless you are in the business of selling said devices.