Something I've noticed in XIV since I started back at launch is that, unlike the olden days, almost nobody uses chat lines in their macros anymore. Not even to brief the party on their status.
Granted, it wouldn't be a good idea to use them on common rotation skills, else the chatbox will be filled up with Joebob Dragoon spamming Impulse Drive. But for certain less used but important abilities its good to notify your party of what is going on. It also livens up the party a bit, since you see people "talking" even in the midst of combat, and it feels less like you're just playing with NPCs.
For example:
My WAR has a macro for Flash that also calls out my current TP. A good WAR doesn't use Flash often, maybe once at an odd pull or when Pacified after Berserk, so it doesn't spam the log. It also has the effect of letting any BRDs know if Paeon would be useful, or if we might need to slow down the pulls.
My BLM has a macro that stacks Raging and Quelling Strikes, and alerts the party that I'm going into a heavy AOE rotation or am otherwise going to be unloading some hurt. This means the tank knows to go all out on hate for a minute, and also lets the other guys know that I'm not slacking off, i.e. Levi Spumes, T6 Bees.
Its just useful. Its nice. People should do it more often.