ForceStealer
Double Growth
Clement Rage said:She falls victim to 'sorry, this is a one player game' induced injuries
This made me laugh

(I really was bummed after it seemed like Yuffie might actually be an AI-controlled ally for a bit.)
Clement Rage said:She falls victim to 'sorry, this is a one player game' induced injuries
Because the likes of her and Cloud are the only ones Sephiroth would ever deign to acknowledge with a fight and not just outright kill.
Sephiroth had absolutely no reason whatsoever to fight Cloud and the others. He chose to because he wanted to give them the fight they so wanted and beat them in battle.
But Sephiroth could have just used his telekinesis to rocket them away or just force-choke em. He literally let them go, just to humor them with a fight. Because Sephiroth likes to fuck around.
We see what Sephiroth does when he's serious or not fucking around. Given the powers at his disposal and the fact he had the Lifestream and monsters of the Northern Crater at his disposal, there's no reason to believe he'd just sit there and let the Tsviets get a shot at fighting him.
He'd blow them up.
Yuffie doesn't show anything suggesting she had Azul covered.
Like you said, she gets to Deepground. nevertheless everyone says Vincent will have to be the one to take on the Tsviets, including Yuffie and her small mountain of Materia. So why is the likes of her a better fit against the Weapons and the assasult on the Northern Cave then anyone and everyone in Deepground either individually or combined?
No, but she does show herself to be a very clever fighter underneath the ditziness, anticipating Rosso's dodge and using that blinding trick, which I would imagine is very effective against someone with Mako supersenses. The issue with fighting Azul is hurting him, which you can do using materia, and I think Yuffie is fast enough that he'd have a lot of trouble hitting her.
She's not.
Deepground would have been suitable to assault the crater, but only once the barrier is down, by which point everyone important enough to give the order is dead and they're in the middle of a rebellion. They'd take a lot of casualties, being so weak to magic, but might even have won out.
Re the Weapons, DGs is almost entirely physical attacks, which we are shown are basically ineffective, even with the entire Junon garrison unloading on them. Yuffie, alone, isn't more effective than DG. Yuffie with KOTR, though... You need that kind of thing (or Sister Ray) to deal enough damage to a Weapon, we actually see that a quite high level party is not enough to take Diamond, and or even hold its attention.
Vincent has immunity to darkness (which Shelke may know about), and has already defeated Shelke and Azul. Yuffie actually is ready to help against Nero and Weiss, but lacks the immunity to darkness, so it doesn't work out.
After agreeing with Cid, Cloud fell in thought.
“Hey, Yuffie. How about this? We’ll give you all the materia.”
“Alright!”
“But I keep it in safe custody.”
“Er— Are you trying to trick a child here! ”
Thinking she was being made a fool, she stood up tall in protest.
“You got it all wrong. Most of our materia are used for battle right? It really won’t be of much use for Wutai. So we’ll just share the ones that will be of use in healing and I’ll keep the rest. I think I’m the one that’s the most experienced when it comes to dangerous materia.”
[...]
“Then lets do this. You return to Wutai but if you feel uneasy without materia then contact me. We’ll think about it again then.”
Cloud was speaking in a gentle tone but in the end, his decision to keep the materia was clear to Yuffie.
@Jairus
Official answers are not to be found for that question. =(