If I remember correctly, the main difference is that you would have to manually sell into the BitPay card, which just spends fiat at that point.
It's like selling BTC into your bank account and then ...
BitPay used a self-custodial on-chain wallet, and the BTC wasn’t sold until the time of purchase. Not entirely different, except it obviously didn’t use Lightning or NWC, and top-ups were manual.
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