What are the perks of cash management accounts (e.g. Stashaway Simple, Syfe Cash+, Endowus cash smart, etc) over a local bond ETF (e.g. A35, MBH)?

Cash management accounts invest in money market funds, these consists of bonds that tend to be held through maturity rather than traded thus less likely to drop in value for the principal

while bond ETFs are held for yield and also traded by the fund which can crash in its own market