Cryptauth is a method of authentication through proof of ownership of a Bitcoin address. It's a new way of signing into websites and apps securely and anonymously through Bitcoin's method of signing and verifying messages. There are a few advantages to this method of signing in. Servers theoretically only need to store one piece of information for each user for authentication. Also, there happens to be a built in method of charging users for microtransactions, through requesting their bitcoin address a payment. On the client side, the ease of transacting with small, micro transactions greatly increases.
There are many ways this system can improve. The most apparent one is the support for Ethereum address as well as other blockchains. With web3 as popular as it is and only gaining steam, support for Ethereum will be crucial. Also, I see the potential to create some sort of API for developers to integrate this into their apps and products. For the user, this product would come in the form of a browser app that holds your private keys to sign and provide a verifiable message to the server. It would also serve as a wallet to make these sort of micro transactions that will likely become more popular.