A substantial welcome bonus is acquisition spending, budgeted like advertising and recovered over the life of the account. The conditions attached are what make that recovery likely.
Accounts are valued over years
Issuers estimate what a cardholder will generate over time through interchange on spending, annual fees and interest where a balance is carried.
A bonus is set against that estimate rather than against the first year alone, which is how figures that look uneconomic can make sense.
Card relationships tend to be long, and the primary card in a wallet often stays there for years, which supports the calculation. Switching requires updating stored payment details across many services, and that friction works in the issuer's favour.
Spending thresholds do several jobs
The requirement to spend a certain amount within an opening period filters out applicants who would take the bonus and never use the card.
It also generates interchange revenue immediately, recovering part of the bonus before it is even awarded.
Most importantly, concentrated early use establishes the card as the default in a wallet, which is the outcome the whole exercise is buying.
Eligibility rules protect the model
Issuers restrict how often a customer can receive a bonus on the same product or family, since repeated claims defeat the acquisition purpose entirely.
Application velocity across all issuers is also assessed, because a pattern of frequent applications suggests a customer unlikely to stay.
These rules are applied at the issuer's discretion and change over time, which is why experiences differ between applicants with similar profiles.
Annual fees are part of the arithmetic
Fee-carrying cards fund larger bonuses because the fee provides predictable revenue independent of how the card is used.
Many waive the fee for the first year, which improves the first-year comparison while relying on retention once the fee applies.
Whether the card remains worthwhile in later years depends on ongoing benefits rather than the bonus, and that is the calculation many holders never revisit.
Assessing an offer on its terms
The relevant question is whether the spending requirement can be met through ordinary expenditure within the window.
Spending more than usual to reach a threshold converts a reward into a cost, which is the outcome the requirement is designed to make tempting.
Beyond that, the card's ongoing terms determine whether it earns its place after the bonus has been collected and the introductory conditions have expired.