CDs and treasury bills seem to pay about the same. My 13 week purchase last week was 4.2 percent. Treasury bill seemed easier since it comes straight out and in from my bank. Treasury bills are state tax free.
I do have some cash in my brokerage account which seems to be only getting 0.3 percent. So SWVXX would be like a mutual fund, you buy/sell and then it doesn’t happen until end of the trading day which would be the one day delay? I could probably do a money market there with some of the cash.