I'm sure this worked before — I have an existing Fidelity brokerage account assigned as a savings account. But I just opened a new brokerage account and there's no longer an option to classify it as anything other than an Investment Account type.
Sure enough, How to Edit Your Bank Account Names and Types says "Note: Investment Accounts cannot be changed to any other account type besides other Investment types."
Is there a technical reason for this change? I primarily use brokerage and cash management accounts (which Quicken has now locked into the Investment Accounts category) as savings and checking accounts to take advantage of better interest rates than at regular banks; I'm not doing any investing in these accounts so it doesn't make much sense to put them in the Investments category.