Why is every store asking me to get the bonus savings card?

Question

Most of the time the clerk just puts in the savings anyhow. Why do I need a card?

Answer 1

Because they can then track your buying habits and send you targetted offers, or worse, sell that info to other companies that may send you more offers.

Answer 2

They push the cards so you'll do your shopping there instead of somewhere else. In most stores, the clerk is only supposed to give the discounts to people with cards - or keytags, which are becoming very common.