Very unlikely, TreasuryDirect is so horrible to use, only if you must like I-Bonds. You just go into your brokerage and buy them on the secondary or even through auctions. TD Ameritrade and Vanguard brokerage accounts make this extremely easy. You can also sell your bonds whenever you want instead of waiting til maturity this way.
Sure its horrible to use. But it does the job, and is directly part of US Treasury auctions, so the prices are provably fair.
Brokerages will skim off a bit off the top when they sell you a treasury. In contrast, TreasuryDirect is direct-from-auction, with the fairest prices possible.
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Besides, its not like a notarized snail-mail form is that hard to accomplish. Back in the day, that was the only way to get any official business done.
Your local bank probably has a notary on hand to sign the appropriate form. If not, look up your Yellow Pages for the nearest notary.
I just checked Google, and there's a bunch of online Notaries. So I really don't expect anyone to trip up over this step.
I personally go to the bank somewhat regularly to pick up $5 and $1 bills. It wasn't that hard for me to have a notary form also signed for Treasury Direct access.
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Besides, there's a chance that you can get everything done online with Treasury Direct. It just so happened that there was some kind of issue that required me to send in a notarized form proving my identity and such.
But using a notary is kind of basic "adulting" skills. There are other government forms that require a notary. (Passports and such).