Tokenized treasuries and real estate report their value once a day, sometimes once every two. When the market moves faster than the oracle refreshes, a loan can already be underwater while the protocol still reports it as healthy. Gold doesn't have that problem, because gold barely stops trading.
Spot gold trades nearly around the clock, five and a half days a week, so a lending desk pricing gold collateral is rarely more than minutes behind the market. Treasuries and tokenized real estate inherit their underlying market's clock. Nights and weekends turn into blind spots where a loan can slide past its liquidation floor with nobody able to act on it.