The objective was to fill enough books to redeem them for household items. After all, the stamps were free. The banks gave you toasters and blenders to entice you. Things haven't changed these days except that we are offered all sorts of new and innovative incentives to enslave us to brand loyalty. We now have reward points for air travel, car rental, hotel stay, and telephone use.
Many credit cards earn points for all sorts of brand loyalty rewards.
You earn points for getting married, going into debt, buying a home, eating out, transferring debt balances, or charging anything and everything on your plastic card. But there are many people who switch credit cards, phone companies, airlines, and stores regularly and often enough to take advantage of incentives and bonus points. They earn enough points to take a free vacation. They know how to play the switch game and take full advantage of the plastic economy. Little do they care for brand loyalty or that the plastic card will disappear the way of the Blue Chip Stamps and the free bank toaster.