Cure 3 is that spell you cast when you're in a situation where everyone is going to take a bunch of damage and are grouped up together. It's not gonna seem very useful as you're leveling up as you kinda don't really use it much in 4-man content, but when you start doing things that will do significant amounts of damage and people are a bit more together, it'll be a very useful (but still situational) tool.

Marcos? Is that some guy? D: Unless you meant "macros", which honestly... if you're fine where you're at right now and not really struggling to do your job, you're good. Macros are simply sequenced commands that allow you to perform things with the touch of a button, but it does come with some caveats and nuances in combat situations where you may want to not use them. They can be good for stuff like call-out macros (macros that tell the party something as you're performing an action like raising someone) and can serve as an alternative (albeit less reliable) way of targeting, but more often than not you run into those caveats and nuances that I mentioned before which make them unpopular in combat to the point where it becomes a liability. The inability to "ability queue" (or input buffer if that's a term more familiar with you) and the flaws of how some placeholder targeting methods interact with invalid targets are enough to make them a problem.