I have IBonds, but they're earning 5+%, and that's not worthwhile right now... Did take some out years ago, and wish I still had them.
As far as I know, any IRA (mine are Traditional) requires the form... see the note on the last page that states facsimiles not allowed.
Keeping money "local" makes sense today, but we've used Money Market funds in the past, when some the larger National banks... ETrade, Metropolitan Life Bank, Discover and a few others were paying a full percent or more than most banks, and even more in Jumbo accounts. Some were paying about 6%.
Wasn't too smart to do that at the time, but we were, are, and will be ultra cautious. Still spend each dollar as if it were the first one I earned as a lifeguard @$.75 /hr.