(a) Worth vs Value.

A 25000 miles award ticket is WORTH only the COST incurred in
accruing / aquiring those miles.

VALUE on the other hand is like beauty.. ie in the eye of the beholder.

The difference is that one is an Accounting entity (worth). While the
other is a goodwill entity (Value). The difference between the two can
be astronomical (eg water front properties, first class air travel, etc).

As far as humans are concerned, VALUE is the actual "benefit" enjoyed
by this animal.. WORTH means nothing.