Earlier quoted context omitted.
You can double that and more if you're married, and use the tax refund trick. But the reality is that 10% on 10k isn't a terribly large amount of money at the end of the day.
You're gonna invest that 10k somewhere in all likelihood, a risk free 10% is pretty much unbeatable, it's higher than most high-yielding (and vice) stocks, but without bearing the risk of capital loss. Seems silly to me not to use I-bonds even if the cap is relatively low, sure wish I could (not American).
The rest I invest in equities, which assuming the US has a functioning society in 5, 10, or 20+ years, will be worth far more.