I didn't have a problem with the no-interest personally but as...

I didn't have a problem with the no-interest personally but as danbradster said there gets to a stage where it itches you as rates continue to rise.

Even today, a person with 100k can buy 2000 AAA ETFs at 50.19 on a Friday afternoon and come Monday morning at 10.00am exactly (all ETFs trade as part of the first group of shares that open) sell into the ask at 50.20 -- yes there is no gain overall after 9.5*2 brokerage but now lets take our bigger accounts with 200k, 300k, 500k etc. 500k can do basically a riskless $100 gain for $20 round trip brokerage for 2 mins work.

If you know you aren't going to trade for a week then these ETFs make even more sense (some would argue transferring large amounts to and from a bank account gets you more but transfer limits get in the way and often with larger cash accounts the interest rate isn't as good after 250k).