Kurapika is overpowered not only against the spiders but against the people and i shall explain why. Okay so in the anime during the Uvogin Kurapika fight, Kurapika reveals his secret ability, this ability is actived when his eyes go scarlet. What this ability does is it makes Kurapika become a specialist and when in specialist form he has complete mastery over all the nen forms including enhancer and Kurapika made no rule saying that he can’t use this against people other than the spiders so yeah only his chains he can use on the spiders but that does'nt change the fact that Kurapika could just go scarlet (as he learnt how to control it at will) and just destroy everyone. However he can only use scarlet for a short time so it’s more like a trump card so Kurapika could use another technique other then chains for fighting non spiders. However he can use still his chains on other people he just can’t use the special abilities on non spiders so combine his normal chains with his scarlet eye and he becomes overpowered against everyone.
Sorry in advance for any grammar or simple English mistakes that were made.