How thoroughly can WINGS phases substitute for a flight review?
All Wings courses that qualify for a Flight Review include both a online knowledge activites as well as required flight activities that are verified by a CFI. These flight requirements generally end up being longer than the 1 hr minimum flight time required by §61.56.  But if you are completing a Wings course for the purpose of insurance discounts, a BRF would be a side benefit.


  To accomplish each Phase of WINGS, you can attend safety seminars,
  take online courses, and demonstrate flight proficiency.


Also, section 1.3 of the Wing Manual states:


  Note that pilots need not accomplish the flight review requirements of
  14 CFR part 
  61.56, if he or she has satisfactorily completed any Phase in the WINGS - Pilot  Proficiency Program


So, the answer is yes, you can use Wings phases as a substitute for a flight review, but it might not be the most efficient way.