For example, you can have a character sitting at the AH (aka GTN) scanning the market. Then you buy underpriced items to resell at a profit. You can control a market easier. Special/rare high demand items you can buy up and relist a crazy high prices. It effectively helps the rich. Yes someone can do that now but this makes is very easy.
Wow had addons to tell players when to push certain buttons. Some of those "QOL" "issues" were alarms so you "didn't need to pay attention".
Example, you need to remove a debuff on a teammate, you had to look for it (aka pay attention) but the alarm points out the player X needs debuff removed. They say since it is already there it should be ok but it really is taking a lazy player route. BTW, if it is there you don't need the alarm.