A CBDC is digital currency issued directly by a central bank. Unlike cash, every unit is a database row the issuer controls — which makes it programmable: spendable only where, when, and on what the issuer allows.
Programmable money is money that can say no to its holder. Expiry dates, category blocks, per-person limits — all become configuration.
The alternative
Currencies that answer only to their holder: self-custodied, no bank account required, no permission sought. That is the design brief SPCTR was built to.