Just to muddy the water even more....
As a procedural controller I often ask an aircraft that I am transferring to my SRA controller to "Contact XXX Radar with your heading". Not technically perfect RT but it will have to do until something else equally safe, short and concise is promulgated. This at least gives the SRA chappy one less call to make prior to turning the aircraft for ident in our primary environment.
Quite often I may ask an aircraft to leave XXX beacon on a heading of e.g. 100 to position it in an area suitable for ident by the radar controller, who may be otherwise temporarily engaged doing the previous SRA.
I have even used headings to ensure aircraft in the same area are divirging if one has suddenly gone IMC and I am trying to get some separation between them until standard separation can be applied.
There are probably loads more instances in which procedural controllers use heading instructions, but these are just a few that spring to mind.