Good point, Efrem. i read a column a while ago which correctly stated that we have been conditioned by the airlines to pay thousands of $$$ for mid-week business trips, and use our hard-earned miles for fairly inexpensive Sat night stayovers trips. The example the columnist (Brancatelli, I think) gave involved paying $900 for r/t LGA-ORD mid-week, then cashing 25,000 miles for Fr-Mon LGA-SFO trip, which could be bought for <$300. [He actually did the opposite, and wrote about it].
So, value depends on your spending habits a lot.