Good point, I-bonds can be redeemed after 12 months, but they have a 3 month interest penalty if you redeem them before 5 years. But that's really not bad at all. So they're long term in that they guarantee their base rate for a long time, but are unusually liquid in that they can be redeemed very flexibly.
I really like those two bonds. I guess that's why they're limited to $10k/yr each :-)
I-bonds are not necessarily long-term bonds, other than the 12 month non-liquidity window up front. No?