I-Bond - To mine and beyond

iBond, Series I Savings Bonds. no FDIC but pretty safe. 5/1/2022-10/31/2022: 9.62%.
Rate=Fix rate (0%)+Inflation rate (floating and adjust every 6 months).
$10K per SSN electronic bonds($25 minimum) and $5K paper bonds($50 minimun).
Paper bonds can only be purchased by IRS tax return at filing(?) .
Expired in 30 years.
Redeem after one year without penalty.
Redeem < 5 years losing last three months interest.
No need pay tax before redeem.
No state and local tax liability.
Can not use 401K or IRA to purchase I-Bond.
If income < 128,650 (2022) iBond interest has no tax liability for higher education expense.
Check https://www.treasurydirect.gov for further detail.