The blue agave plant is used to make agave nectar which is a liquid sugar like honey. I use it all the time since it is a low glycemic sugar.
They cut off the agave leaves and extract the agave in the which they make tequila.
There were four types of tequila there for tasting; one was Almond flavored tequila. I don't imbibe but my new friends from Australia said they'd drink my shots.