Bitcoin is more of a commodity than a security. However, you can think of it as a security because it is an investment in a technology.

I think of altcoins as securities because they are often investments in projects. They are also commodities.

The SEC chairman seems to be concerned with projects that are centralized. If there is one person or business offering a coin or token on the market and promising that the business will do something gainly so that the coin or token increases in price then that is a security. The regulation comes in when the person or business is obliged to share certain gains with the token-holders I suppose. In cryptocurrencies, the gains are automatically realized to investors through the blockchain even though whales or early investors get a lot of the profits. The early investors get the profits through demand for the coin and use of the project.

Given the corruption in the financial system and the ways that companies are able to massage their stocks to give themselves profits or manipulate the price of the stock, I don't know where the SEC gets off trying to regulate cryptocurrencies. To have a better market, which should be the goal, they should let the blockchains regulate themselves and make the stock market compete with it. It will keep the stockmarket honest and keep the corruption in check.