I think Regulation Q is a vary good idea. 'Checking' accounts that pay significant amounts of interest have long been the source of instability in the banking sector. And with FDIC inshurance covering the depositor's risks there is a significant moral hazard for banks to do ever more shady things. Just think about it for a second as a depositor your covered by FDIC and some bank is offering you 6% ROI why do any sort of due diligence just take it and let the tax payer bail you out if anything bad happens. And now your a competitor, you know that it's risky to compete but your also losing all your customers so you might as well take stupid risks vs just plain going out of business.
I don't think your story holds up. Checking accounts pay nowhere near 6% interest. Mine is currently paying 0.10%. Savings accounts are FDIC insured and Regulation Q did not forbid them to pay interest, it was just harder to get your money out. I don't think any professional economist believes that interest on demand deposit accounts has ever caused a crisis or been a significant cause of systemic risk. It was an anti-consumer regulation, plain and simple.
