That's for bond purchase and payback in Brazilian Reais with a bona fide government (with Lula back).

To guarantee an 8% payback in crypto is a completely different game, and there's a significant downside for someone taking the deal. The expected return rate is always going to be negative on a proposition like that.

The classic ‘risk free’ asset is US Treasurys, the US has never defaulted on its debt. Any yield above the risk free rate has implied risk, Brazilian bonds yield 13% because Brazil has defaulted on its debt several times. Brazilian bonds are at least an order of magnitude riskier than US Treasurys, and probably more than that.

FTX was paying well above the risk free rate (currently 3.25-3.5%, it’s been climbing since January 2022), implying they were taking risk to earn the yield they were paying.

I Bonds are an exception since everyone is capped at $10K and the rate changes quarterly based on inflation. BlockFi and other DeFi platforms were offering 8%, but had a minimum balance needed ($100K in most cases).

The government is losing money on I bonds

I bonds are subsidized by the US Treasury (this is why there’s a purchase limit), which has never defaulted on its debt.