Well some of the Japanese rock band quite skillfull and unique.Their songs also nice to listen to and probably could help a bit on guitar skills if u learn and played the songs. But it only helps u to go only a tip further. If u like to learn guitar and loves to listen to japanese rock band, I suggest u watch their live concert but at the same time find some random famous international rock band(take Guns n Roses for example) and watch also their live performance.Compare both and u'll know why u couldn't go further.