Bitcoin is slowly spreading worldwide that's why it is not surprising that payments for some of the professionals are in cryptocurrency. Since they are lawyers, they know what are the applicable laws. In my country, I don't know any professional services that accept bitcoin or ethereum but sooner or later I believe, there would be someone who would consider it as payment option. The accountants, lawyers, engineers, doctors etc. maybe would consider it. Bitcoin is not yet legal but not banned in our country so maybe when bitcoin is regulated then they would accept it.