Why the deposit answers the underwriting question. A card issuer's problem with a thin or damaged file is that it has no evidence of repayment behavior to price. A deposit removes the need for that evidence, because the exposure is already covered. That is the whole mechanism, and it explains both the product's accessibility and its economics: the issuer is lending against cash, so it can approve almost anyone, and it earns from interest and fees rather than from taking credit risk.
The deposit is not a payment, and this is the most common and most expensive misunderstanding. A $500 deposit against a $500 limit does not mean purchases are being paid for out of the deposit. Purchases create a balance owed to the issuer, that balance is billed monthly, and if it is not paid in full the grace period is lost and interest runs. It is entirely possible to owe several hundred dollars in revolving interest over a year while the deposit sits in the issuer's account earning nothing for you. The deposit is drawn on only if the account defaults.
Regulation Z contains an anti-fee-harvesting rule that bites hardest on this product. 12 CFR 1026.52(a)(1) provides that "the total amount of fees a consumer is required to pay with respect to a credit card account under an open-end (not home-secured) consumer credit plan during the first year after account opening must not exceed 25 percent of the credit limit in effect when the account is opened." Because the limit on a secured card is small, the dollar ceiling that 25 percent produces is also small, which is exactly the discipline the rule was written to impose on cards marketed to people with no alternatives. Read the carve-out too: under (a)(2) the limit does not apply to "late payment fees, over-the-limit fees, and returned-payment fees," nor to fees the consumer is not required to pay. So it is a cap on the price of having the card, not a cap on everything the card can ever charge you.
A second disclosure exists precisely for the version of this product that bills the deposit to the card. 12 CFR 1026.60(b)(14) requires that where an issuer requires fees for the issuance or availability of credit, or requires a security deposit, and the total of those required fees and deposit charged to the account at opening is "15 percent or more of the minimum credit limit for the card," the issuer must disclose the available credit remaining after they are debited, assuming the consumer receives the minimum limit. A card that arrives with much of its limit already consumed by charges is a recognized enough pattern that the regulation makes the issuer print the remainder.
The small limit has a mechanical consequence worth planning around. The ratio of reported balances to credit limits is computed the same way whatever the limit is, so a $270 balance on a $300 line reports at the same 90 percent as $9,000 on a $10,000 line. The credit utilization page covers the ratio itself; what belongs here is the practical implication that on a secured card the reported balance, meaning the balance as of the statement closing date, is the number that needs managing, and that keeping it low means spending a small fraction of an already small line.
Graduation is a contract term, not an entitlement, and it is the question to settle before applying. The Bureau's description says the limit "may be raised" and the deposit "may" be refunded, and that permissive wording is accurate: nothing requires an issuer to convert a secured account to an unsecured one, or to return a deposit on any schedule short of closing the account in good standing. Three things are worth asking in advance. Is there a documented review, and after how many months. Does the issuer convert the same account, which preserves its age in your file, or open a new one. And does the card report to all three nationwide credit bureaus, since a card that reports to one is doing a third of the job you opened it for.
On cost, the Bureau's own summary is the honest one: "Fees and interest rates can be high for secured cards, but using one can help you to establish a credit record."