It takes forever, it slows me down a ton, and a doesn't do all that much more damage than a normal attack. In fact, damage-wise, I'm usually better off just hitting the monsters twice with a normal attack.
The only benefit that I can see is that a charged gun shot usually seems to travel farther than a normal gun shot, but that seems to be of limited value.
There's plenty of reasons to charge.
More damage, status ailments inflicted only when charged, range attacks on sword, effects not achievable on a normal strike such as knockback for calibur charge.
When you level up weapons, the time to charge decreases for that weapon when you reach level 5, and again when you reach level 10 (the max level).
And different weapons have different charge attacks.
Some charge attacks are very useful, like Calibur... Awesome on Lumbers. Get them against the wall, charge at them, and you do multiple hits
I know Autoguns are terrible, but I can't bring myself to stop using them. That being said, unloading a salvo of sixteen hits on a mob at point-blank range is absolutely devastating. Assuming they don't freaking Matrix Dodge it all, that is. >.<#
Some weapons have effect that only happen when charged, and bombs only work when charged