Can I Beat “High-Yield” Savings Account by Putting My Money Elsewhere?

I have ~$5K in a solid *High Yield* Savings Account. It’s earning 5.25%. Meanwhile, I have a “Rewards Checking Account” with Discover that’s earning 5% in a rotating category, such as gas stations or groceries (and, as I understand, it’s not hard to maximize the $300 category limit). This year it’s gas stations and next year it’s groceries.<br><br>So I was thinking, why not just use the Rewards Checking Account to earn 5% on gas stations or groceries and put my money to work elsewhere for the other 10% of my monthly spending?<br><br>And what if I were to use the money I would have put in the “High Yield” Savings Account to say, take out a cash advance on my credit card (essentially a 0% loan) and put that money in a longer term (but similarly low risk) account like a 12 month CD (6.25%) or something even riskier but potentially more rewarding like REITs or Index Funds?<br><br>Has anyone tried anything like this?<br><br>TLDR - Instead of putting money in a “High Yield” Savings Account, put it in a Rewards Checking Account and boost total returns by using the money you would have put in the Savings Account to take out a 0% cash advance on your credit card and put that money in a longer term/ riskier account.