The NFCU offers a reloadable, prepaid debit (Go Prepaid) card that can be funded by the CU credit cards.
The funding is treated like a regular transaction with the grace period. You don't earn rewards though.
This gives 30-50 days possession of borrowed credit card funds if you make the charge on the credit cards' closing date. Since I prefer not to have high balances, reported to the CRAs, the credit card funds will be kept 30 days and have the money repaid in between credit card closing dates.
This creates an opportunity for safe arbitrage. Just put the money in a high interest checking account. Earn interest for a month. Repay the credit card before the next closing date. Rinse and repeat each month. I want to try this with about $10000.
But I believe the scheme is dead in the water.
The problem is getting money of the card efficiently. The Go Prepaid does not offer an account number or routing number, as far as I know, so ACH is not possible.
Money transfer services like Moneygram, Western Union, Paypal, Square, Venmo, etc all charge a percentage per transaction that is greater than the interest I would earn.
Amex Bluebird, Serve and their ilk are not trustworthy and should never trusted with your money based on my experience.
Buying money orders at Walmart for $10k would involve buying 10 separate money orders @ $.88 each on a ongoing monthly basis. Each money order would have to filled out and deposited to my checking account. The fees and the time suck cancel out the profit. Plus the risk of raising red flags at Walmart and my bank, accused structuring.
Unless I can sit at home and figure out a near zero cost way to digitally transfer the money from the Go Prepaid, then it is best forget about it and move on.
