It's a way to add two-factor authentication to your website or app. Instead of having people log in with just username and password, they'll also have to enter a code. They get the code from the Authy app on their phone.
(PS I'm not affiliated with Authy, just trying to be helpful.)
Basically, yeah. Goes well with platform-as-a-service for software-as-a-service, full-text-indexing-as-a-service for software-as-a-service, payment-as-a-service for software-as-a-service, etc.
Easier to snap these components together than roll your own.
(PS I'm not affiliated with Authy, just trying to be helpful.)