Well, yea. SIPC only covers cash deposited with a broker for the purpose of purchasing securities. I suppose the "purpose" of depositing cash in these account

Well, yea. SIPC only covers cash deposited with a broker for the purpose of purchasing securities. I suppose the "purpose" of depositing cash in these accounts is to purchase T-bills for the 3% but I'm not sure that's immediately apparent to their customers. This isn't a checking account. This is a brokerage account with a cash sweep that comes with a visa card.