I agree that it is important to understand where yields comes from. But if one holds a stable USD balance, I believe it possible for it to accrue interest/yield from the counter party on the other side with a bitcoin balance. I'd prefer an eventual mechanism like discreet log contracts (#DLC) or some derivative contract that is not dependent on a company like Tether. I'm hopeful for work that organizations like #10101 (10101.finance) are doing.
Discussion
The yield comes from the fact that to accrue interest, fiat issuers will expand the money supply. So the interest paid is always well below the rate of monetary expansion, so effectively, they are robbing you to pay a reward that is a fraction of your lost buying power.
That is why it is so important that (in the US) the government convinces us that CPI is accurate and below 5%. Because if we realized we were getting 4% interest on 15% monetary inflation, we would revolt.