Other times they may want to reduce your available credit on existing cards before approving you, especially if you apply for a business card. (travelcodex.com)
From a common - sense standpoint, you did the right thing by accepting this 0 - interest card offer, especially since you had existing card balances incurring (probably) high interest. (speakingofcredit.com)
They would each sign up for all 4 cards, as they had a relatively small number of existing cards but excellent credit history. (pointsaway.com)