How is the USD Cash Yield portfolio different from fixed deposits?

There are a few key differences between a classic fixed deposit account at a bank and a USD Cash Yield portfolio.

Fixed depositUSD Cash Yield Portfolio
DescriptionAn account opened at a bank that pays a guaranteed interest rate after a stipulated time period.A portfolio that invests into short-dated US Treasury Bills. 
The rateYou lock a guaranteed rate.The rate is a projection and moves along with US Treasury Bill rates. 
Lock-in periodVaries from 3 to 12 months on average.None
Minimum amountUsually requires $20,000+ of new funds to earn preferential interest rate None
Deposit insuranceInsured under Hong Kong’s Deposit Protection Scheme for up to $500,000 HKD per depositor per scheme member.Uninsured