It’s worth noting that bond prices tend to move before the RBA cuts rates.

In fact, one of the things that are a decent predictor of future rate moves are the bond markets. The lower rates become priced in before they happen. So if you thought you could buy bonds, then when the RBA cuts rates, they’d go up in price, then it just doesn’t work that way.

As a place for holding cash short-med term it makes sense. But I reckon you’d likely find that a mortgage offset is superior for two reasons: the rate is likely to be higher, plus the return is tax-free (assuming it’s your residence not an investment property).

You might get fortunate and get gains from whatever has not been priced into bond markets already, but that would probably be more luck than anything.