Your experience with addons that tell people exactly what buttons to press?

Hi. First of all, I haven't raided seriously in WoW since retail WotLK, so I really have no idea what it's like now. However, I'm really looking forward to WotLK Classic, and a thought recently occurred to me, which is that, with some specs being more complicated than any I've ever seen before in Classic, players who use addons that tell them exactly what buttons to press would probably perform better than those who don't in some cases. What do you think, is this true in your experience? Are these types of addons common in retail WoW raiding where specs have been more complex for a long time?