Originally Posted by
PyurBlue
That's not actually true. If a lone PLD is trying to carry a group after a near wipe they'll probably FB > RB loop instead of finishing the combo to keep up MP for Clemency. If they were forced to go on to RA or GB, they'd risk running out of MP much faster. Something that applies to all classes is restarting a combo on a low HP enemy so that you can attack subsequent enemies with a high potency attack. So if there are 2 mobs around, and one has only a tiny sliver of HP left, you're better off breaking your combo on it to attack the next mob with the second portion of your combo than using the combo ender and attacking the next mob with the weak combo starter. The exception would be if they were both next to each other and you could switch targets quickly, but that might not always be the case.
In the first case, automated combos could be crippling and cause what could have been a clear to become a wipe. In the second it's just optimization, but I think it's fun to pull off, and it's something you'd lose if the combo system forced you to complete a combo.