Simple fiat stability. This recent crash in the fiat price caused a lot of bitcoiners to lose fiat purchasing power. And everyone’s bills that matter (food, water, shelter) are denominated in dollars. STRC protects your balance and pays you out by stripping the volatility out of BTC.

So in other words, as well as the coupon, the appeal is that it retains the $100 peg during a downturn (or thereabouts)? How feasible is this during an extended bear market (i.e. people losing confidence in the underlying asset) without raising the coupon to unrealistic levels?

You could do this but you will end up with less bitcoin versus people who use fiat and never sell. Plus the tax structure isn’t favorable for bitcoiners to do this. Until producers take Bitcoin as payment fiat will have utility and thus products like STRC will have market fit.

Tax treatment aside, my point is that as BTC outperforms STRC over the long term, the BTC holder would on average outperform the STRC holder. That's essentially Saylor's game, right? The opportunity cost of owning STRC is that you're not owning BTC instead.

I guess for smaller positions where you can't average out the vol, STRC could make sense.