Other people they used bitcoin for illegal transaction. Someone told me that one of his facebook friend used bitcoin in illegal transaction, like money laundering, so i believe that everything can be used in illegal because in this world lots of people are devils when it comes to money.
make it hard to used for any illegal activities / transactions ,
as bitcoin come with its anonymous untraceable people have so many evil idea with bitcoin ,
include the money laundering , pay someone for a dirty job etc.