I got chewed out by my favourite ATO on my last renewal for giving GPS/RNAW waypoints in my CTAF calls.
His words were something along the lines of,
"the average VFR would have a fecking clue where 'Waypoint Wiskey Charlie' is"!
So I now tune GPS #2 (Forkair Ops Manual dictates a minimum of 2 for IFR ops) onto the aerodrome reference point and say something like,
"WWW is XX miles northwest (or whatever is appropriate), passing YYYY on descent, inbound in the Rwy ZZ GPSRNAV Approach".
That seems to keep everybody happy!
Dr 