If you buy 10x $1000 (or 20x $500) bonds and cash out less than the full amount over the course of a year, you'll still come out ahead of whatever interest $BANK was going to pay you for the same funds in your savings account.
It's not a good emergency fund at first, but if you roll a few years into bonds then it can act as your fund after a few years.
The part of this that escapes me is that after a certain point one would more than likely have been, by historical accounts, better off the invest in equites. Then again, I am more of a proponent for emergency plans instead of just emergency funds.
However, if one wants to hold a portion of bonds and a sub-portion of said bonds happen to be I-Bonds, then I see no issues with that.
I’d agree that long term you’d be better off with more typical investment strategies. I-bonds are good right now, but as the bulk of any young persons investment it wouldn’t make sense. Savings rates have been low for some time now so I-bonds can serve a role for emergency funds if you can get them to older than 12 months safely.