The point of CPU-only is the millions mass your coin can gain in the market since anyone can download and get some coin. Mass leads to network effects, which leads to competing against Bitcoin effectively, given Bitcoin only has 350,000 users.
This is not a well-thought argument. A CPU coin is likely to be dominated by expensive CPUs and/or CPU farms that are available for time purchase. Those with low-end CPUs will be forced to upgrade to remain relevant, but the simpler and perhaps more financially sound option is to purchase the currency in lieu of mining it. This is the *exact same* scenario with GPUs. And it also makes sense economically because if everyone is a miner, no one is demanding to trade fiat for it, and all value must enter the coin via burning electricity.