Only if you can genuinely afford it without taking on debt. The strategy is powerful, but not at the cost of a credit card balance at 24% interest.
The strategy only pays if the cash you use is cash you actually have.
Do it when:
Don't do it when:
The decision is per-expense, not permanent. Pay the $80 copays out of pocket and use the card for the $4,000 surgery if that's what your cash position supports. Every out-of-pocket dollar you document is a dollar of future tax-free withdrawal — the ones you can't afford to float simply don't participate.