It places a paradox in the sense that, death is a requirement for the Nen to become stronger, but it´s being used to revive it´s own user, without we viewers knowing what happens to the said nen afterwards, it places a possible paradox, it shouldnt be strengthned without the user´s death but is used in after power-up to revive the user, but if it required the user to stay dead to be strengthned, what does it happen to it after revival? If it was a simple, death and power-up , then it´s bad, because it allows the user to cheat death and gain a power-up from it, granted, Chrollo in a way cheats by also having nen strengthned by death abilities, but at least in context it involves the permanent death of the former user´s power to bend the rules of Bandit Secret, in Hisoka´s case he did all of this with his own Bungee Gum.
Point is, powering nen up by death, is a interesting aspect, but if it´s used for this types of things it starts enabling problems paradoxs, being a simple one but I do agree it might not be a paradox if we get some insight on the whole thing, involving a power down to Hisoka´s Bungee Gum after revival, that he somehow can get past by with established contracts, thats the only way the whole thing will make any sense to me, also having him powering down from the death strengthning nen, back to his former nen level at his time against Chrollo, isnt going to cut it out either, since it can potentially enable Hisoka to cheat death many more times.
Also wouldnt like to see Hisoka defeating Chrollo at the long run due to this revival, if he were to power up from it, just as a excuse to make Chrollo´s defeat more bearable to watch, but I will be ok with it, as long as it involves, some strong placed contracts.
I wonder if Togashi is gonna to make the Hisoka/Phantom troupe chaps take a while now after HxH restarts the chap releases, to think things out about this whole thing.