Quote Originally Posted by Ghallo View Post
This.

With WoW's old /castrandom you got a spell off with every single keypress. If you had 5 spells and 4 were on CD you had a 100% chance of casting the 5th spell on the next keypress. To get this same result, you would have to hit every spell button at the same time. However, you could use "Dorandomhotkey" for 40 seconds of pressing and still never get that 5th spell to be clicked (the odds of that are small, but long enough to be relevant). The more abilities you tried to map this way the worse it would get. In the end you would be better off taping pennies to your num-pad and one press = 10
This is not how /castrandom in WoW used to work. Even if 4 out of the 5 spells were on cooldown, castrandom would still attempt to cast them. It would not stall on them like it does now.

It was used because if you were spamming the macro fast enough, you're basically sure to get off a spell in a good amount of time. Sure, there is a small chance of always hitting the spells on cooldown, but in practice that doesn't happen.