First of all we don't know if Danzo used KA against Nonou. Actually I doubt he would have since again, he wouldn't have had Shisui's eye at that point in time. Kabuto is 23 years old, he was brought to that village when he was 3. Three years passed since Kabuto arrived and Danzo came there to talk to Nonou. so Kabuto was 6 at that time.
So that was 17 years ago, Shisui died 8 years ago. Therefore Danzo DID NOT have Shisui's eye when he met with Nonou.*1 Nonou had NO choice but to change her mind, he wouldn't have even needed to use KA even if he did have Shisui's eye at the time. If she didn't go on the mission, the orphanage would have lost its funding, and, as implied by Orochimaru and the other Ninja with Danzo at the time, they would have attacked the village and stolen children. SO Nonou has no choice but to go with them, KA was not needed. Not that Danzo has Shisui's eye anyway.
Secondly, you are acting like if Danzo had a Space-Time Jutsu that it would be like Kamui. Which is obviously not true.
According to YOU, Danzo was Tiger Stripe Tobi, that Tobi has exactly the same abilities that the Orange Mask Tobi used AGAINST DANZO right before Danzo fought Sasuke*2. We know all about that Jutsu he uses, he sends people to alternate dimensions when he touches them, and can phase his own body out and let attacks pass through. This can only happen for 5 minutes at a time though. It is also the same exact Jutsu that Tiger Stripe used against Minato. So how could Danzo have used this Jutsu against Minato without Shisui's eye? Shisui's eye doesn't even have this Jutsu. Danzo didn't use anything like it during his fight with Sasuke, and your reasons as to why are not valid.
That Jutsu is not like Kamui, it doesn't take time to use it again, so why would he not use it against Sasuke.*3 That Jutsu does not even use MS, the only reason Danzo wasn't using Shisui's eye was because he couldn't use Shisui's MS. He still wouldv'e had regular Sharingan though, which is what the Space-Time Jutsu uses, so why wouldn't he use it?
He wouldn't have had to waste Izanagi, along with his eyes. He could have just phased through any of the attacks Sasuke did.
And I would think Danzo would want to keep his 10 Sharingan, why? Where is he going to get more now? Tobi has basically every single Sharingan, Danzo would not be able to put new Sharingan into his arm to replace the ones he lost due to Izanagi.*4 So he would rather use a space-time jutsu that let's him do basically the exact same stuff that Orange Tobi does. Oh he doesn't have such Jutsu's, that's why he didn't use it.
Do you really think that Tobi would have the EXACT same jutsu's, and be two DIFFERENT people who posed as him? How would Tiger Stripe Tobi and Orange Mask Tobi have the EXACT SAME JUTSU if DIFFERENT people were each?
It's not just ANY Jutsu, it's Jutsu that ONLY TOBI has been shown to have. NO ONE ELSE can phase through attacks like he can, and no one else can absorb ENTIRE people into a dimensional void he created.*5
ALSO, Danzo's left arm is not made up of Zetsu like material...well neither is his right arm for that matter.*6
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Oh look, Tobi's left left hand is falling off with no blood, and all gooey like. What is this like? Zetsu? Yes it is. Danzo has no such thing. Obviously according to you, since Danzo IS that Tobi in that picture, shouldn't Danzo have such an arm in current time? He had no such thing fighting Sasuke. Tobi is one person, and has always been one person. Danzo as Tobi is the most idiotic thing, worse than Obito is Tobi.