I'm a newbie with some technical skills, but not a lot.
Should I be using MetaMask for added security?
What does MetaMask do for me, exactly?
Also, MetaMask seems to only work for Ethereum-based coins. Is there an extension like MetaMask available for the other coins?
MetaMask is for securing ERC20 supported wallets and can make you comfortable using the site for trading and holding. It allows you to easily access dAPP with the use of the private key and allows you to visit the ethereum sites. Also, metamask make it more accessible and more secured for all the users of ethereum. This plugin can also interact in the ethereum blockchain which is very convenient and interact with different smart contracts.