If limit is 5000 and iPhone is 4000, after swiping, the limit only left 1000. The 4000 limit converted into instalments. Must pay on time or there will be late fees. If defaulted, the iPhone is still yours but the debts will pile up higher until fully settle.

Cannot buy lor.

No need for emergency use ka?

If suddenly need to pay for medical or repairs, CC is a backup. If maxed out, later cannot use.