That autoattack turns off for any reason without you deciding you want it to go off.
As a tank it sucks, As a rogue it sucks. As a bard it sucks. It just sucks period.
You're in a huge mob fight with a full party. You can barely see with all the powers going off around you. So you click displacement, go stealth, jump into the mob, drop a web trap and bounce out. Then you spin, click power boosts followed by unbridled fury and giggle maniacally as you prepare to unload for monumental damage guaranteed to take out half the mob at least.
10 seconds in as you click different clickies you notice there's not enough sounds of bolts hitting. No screams of pain. No nothing. You retarget. Only seconds are left in your UF. Then you realize the GDMFBS#&$((* autoattack has shut itself off again and within seconds 'poof" party wipe.
It's beyond annoying.