I'm a buyer of I-Bonds this month. They won't make me more prosperous though since they only track the CPI now. (The only exception would be if serious deflation strikes again, since I-Bonds cannot deflate.)
That said, a 4.6% rate based on the inflation of the last six months is better than most alternatives. Keep in mind that the rate will reset on November 1st. The only thing locked in is the 0.0% fixed rate above and beyond that of inflation. At 0.0%, there is no above and beyond.
A reminder that if you are considering buying I-Bonds this month, there is no hurry. There is no benefit to buying at the beginning of the month. I therefore tend to buy near the end of the month.