I hate countdown macros. Overly annoying.
Any in-battle macros are also going to impede your flow over time as they can't queue like an ability can. Even if it's just to announce you've done something. I can't tell you how often a Provoke macro never actually used Provoke, ending in a very dead other tank.

As someone else mentioned, crafting macros tend to be the only useful ones. Perhaps lengthy explanations or gear lot rules perhaps. But not for anything in battle itself.