Why dont you create your own blockchain network?
Creating a separate blockchain is not that easy. They dont want to waste time to develope their own blockchain, that would also slow down the development of their chips.
You are right, they can still use erc20 first and then enabling PoS blockchain, i see this many times.
I personally believe that their chip is the only way to bridge the dichotomies between the real world and blockchain technology and fix many of the problems present in cryptocurrencies, the IoT, and AI space