Well, treasury bills are a sure sort fund , that promises 100% repayment with almost ZERO chances of default. Apart from being able to return a sure sort return, they are not something one would want if getting a high return is you priority.
This is why people go for other stocks/G sec to get a higher return
Not if you want to play it safe.
If I'm correct, you will only earn a few cents after 90 days after investing thousands of dollars.