Credit cards don't just offer chargeback capabilities. They offer pro-active fraud protection. They alert you for all kinds of threats, data breaches, double-charges, etc. They will sometimes lock your card and not let a payment go through, if it is suspicious, unless you perform extra confirmation via email/text/push. They offer virtual cards that you can activate or deactivate with any given vendor, to improve your privacy, security, and control.
Having your card stolen, either physically or virtually, becomes much less scary.
When used responsibly, with rewards programs, the numerous benefits over cash make sense even in the unusual case where cash payments get a discount.
Zelle and debit cards have similar kinds of protections that make it safer than cash, and there's an audit trail. Though, it is more dangerous than credit cards.
And, obviously, credit cards let you borrow money which provides flexibility to allow payments even if your paycheck hasn't yet arrived. And occasionally, going into debt intentionally can be wise, when making an investment.
Government programs could offer these kinds of features, but betting on long-term competence, customer service, and innovation in the public sector is a losing proposition.
Having both public and private options works as an intermediate approach.
But, particularly for lending, the process of determining credit-worthiness is not a government specialty, and making it subject to the political process seems like a losing proposition for taxpayers.
Payments are a more valid area for government involvement, but even then, I'm not sure what it could offer that Zelle doesn't.