Credit versus a variable benchmark

Which of these is a usable benchmark for a PT on a yield-bearing dollar?

• "DeFi lending pays about 4%"
• "Aave"
• "USDC supply on one named lending market and chain, 4.0%, as of today's date"

The variable rate you compare against touches 7% for a while. When does floating beat the PT?

• Whenever the variable rate is above the PT's yield at any point
• When the variable rate's average over the PT's whole life is above the break-even
• Never, because fixed always wins