I completely agree with this - you don't want to expose yourself by pouring 100% into your punch. Problem is that Uvo's 20% is 20% of his total aura output, rather than a case of him allocating 20% to his punch. I say this because Uvo goes 100% at a distance from Kurapica and Kurapica remarks that Uvo is emanating "an incredible amount of aura." Unless he's already shifting all his aura into his fist at a distance, (he isn't, his whole body is pulsing with aura and with no particular emphasis on his fist) it's clear that this implies that Uvo was artificially using a fraction of his aura. Why? For fun? Despite the plot holes, inconsistencies and such throughout HxH which makes the logical interpretation the wrong interpretation, I think this was what Togashi really wanted to express. It was a means for him to "up the stakes". I suppose it was effective from a narrative/writing standpoint but in the end no matter how you twist it it's hard to justify. Considering how little of Uvo we've seen the only conclusion to make is that "he's incredibly careless", in my opinion.
Another example of Togashi not making sense is the thing about Kurapica's In cloaked chain already being around Uvo since the blunder he made when he was fighting at 50%. If the chain was already around him, why would Kurapica be surprised about Uvo's whereabouts, In or not?
I realize the way Ubogin punches more or less the same the entire time but I still think if he does a Big Bang it has a longer recovery time compared to a punch at lesser overall power output. HXH isn't a series where people randomly used reduced % of their total power just to be cool.
At the 50% mark, Ubogin said Kurapika will regret not chaining him, which implies he wasn't chained. Kurapika's ability is not unlike Hisoka's, in the sense that he can obviously chain someone while attacking directly too and has no reason to hide it unless he's trying to sneak attack. At that point Kurapika wasn't hiding his chains, so Ubogin must mean chaining as a follow-through to his normal attack. But I think Kurapika didn't chain him becuase he knows Ubogin is at 50% so it's possible he gets an extra burst of power to do something unexpected, so Kurapika prefers to wait until he's at 100% to ensure he can't do anything unexpected. Again this is only possible because Kurapika could tank his 50% damage output. If he did not he'd be forced to try to chain Ubogin earlier, and Ubogin possibly could avoid it by increasing his aura since more aura = more speed too.
---------- Post added at 02:55 PM ---------- Previous post was at 02:49 PM ----------
I think Uvo used 20% of his aura because Kurapika is a conjurer.Conjurers and manipulators are the weakest physically so their defense is too.For a guy who used all his potential in brute strength I think his reasoning was pretty logical.
Well the 20% is enough power to win but the question raised up is why not just use 100% if it looks like his punching animation is pretty much always the same? After all being deader is better than just dead.
My argument would be that although Ubogin's attacks look identical at 20/50/100%, he must have longer recovery while doing the 100% Big Bang compared to just the 20% test case. In fact, in both cases we basically have fight go in this format:
Ubogin punches Kurapika
Kurapika stagger back
Counterattack with chain
In the 20%, Ubogin avoided it. In the 100%, Ubogin did not. Kurapika said that it's because he used In and Ubogin was talking, but I think part of it must be because Ubogin cannot immediately recover after using the Big Bang. That is, that punch must use enough power that he's momentarily frozen after the impact just from using up so much aura. If there's no difference in recovery time between 100% and 20%, then he might as well start out at 100% all the time.
---------- Post added at 03:00 PM ---------- Previous post was at 02:55 PM ----------
Note that in most cases, using 100% would also be problematic in the sense that after you attempt a 100% output attack, you'd be pretty vulnerable to any counterattack. It doesn't matter in Kurapika's case since his chains are basically one hit kill (you go to Zetsu and it's game over if it connects) but against most opponents perhaps it is wise to leave extra aura to defend.
Also, I guess you can say that if someone's at 100% for an attack then they got no aura left to do things like Gyou, which makes it less likely they'll see through your In. Ubogin at 20%/50% presumably can use Gyou any time and might see through the In that way, but if he's at 100% by definition he has to use all his power in the Big Bang and wouldn't be able to use Gyou immediately even if he wanted to.
Although the manga does not make it very clear why there are drawbacks to go 100%, I think we can assume it must leave you more vulnerable to any kind of counterattack/surprises so if you know 20% is supposed to knock someone out, you wouldn't use more than 20%, not because you underestimated your opponents but that having an 80% of aura in reserve helps you deal with any surprises, provided you know your 20% is sufficient to win.