It is not a legit currency because it is not regulated by the government, it is not implemented by them but someone just invented in it and they don't want people to become victimized of this as they were thinking that it was purely a scam.
Bitcoin is good not a scam, Some people are bad making bad for bictoin use it personal interest how to make earn using bitcoin in bad ways.
Regarding for the legality speaking for bitcoin there have possible in the future become legal worldwide if bitcoin knows by the government how to control as centralized currency.