Actually, legal has stated this over and over again throughout the years. Just grabbing one instance from this
letter:
With respect to conducting the flights for compensation, your request notes that the pilot, who holds an ATP certificate, argues that any time logged on these flights should not count as compensation because building general aviation flying time in a Cessna 172 does not advance his career. Generally, accrual of flight time is compensation and the FAA does not enter into a case by-case analysis to determine whether the logging of flight time is of value to a particular pilot. (Legal Interpretation to John W. Harrington, from Donald Byrne, Assistant Chief Counsel (Oct.23, 1997) [1997-23].