Paying for your air travel is the most effective way to get maximum value from your points, but airlines restrict the number of seats available to points-paying passengers.
That applies especially during peak travel periods when airlines can fill that seat with a farepaying passenger.
You may also have to fork over cash to pay for taxes and surcharges and that takes the shine off the deal.
Upgrades from economy to business class are an attractive proposition but you need to book one of the more expensive economy class seats to qualify.
You can use points to buy luggage or noise-cancelling headphones from your airline's award store but the rate of return for your points is worse than if you were to use them for flight bookings.
Ditto for using points to make hotel bookings. You can also sell frequent flyer points.
Flip My Miles is one of several brokers. This could be smart if you have points that are close to expiry.