The venn diagram of internet users that read about super specific financial products, decide to buy them, while not even understanding the need to keep an emergency fund such that a move like this leaves them with under $200 in their account seems to be growing. It seems to be a weird mix of wall street cosplay and financial ineptitude.
You can take the money out of an ibond with a small penalty after a relatively short time. So it's not a huge risk if you have enough short-term credit, etc, for an emergency before the time comes when you can cash the iBond.
Is anybody else just sick to death of the term "emergency fund"? If you go to /r/personalfinance, every other comment is reminding people to stock up their emergency fund. Towelie says, "Don't forget to bring a towel!"
I'll tell you about my real "emergency fund": In an actual, living emergency, every single dollar I have, in every account, even my IRA, and all my credit lines combined, are my emergency fund. That's the nature of an emergency. If I empty out some specially earmarked emergency fund, I don't tell the doctor to quit taking the bullets out of my spleen because I'm tapped. "Sorry, can't touch my HYSA!" (HYSAs are another butt bug of /r/pf)
What people mean by "emergency fund" obviously is their "don't stupidly overdraft your checking account fund", but they never spell that out.