OK, once again answering my own question:
The reason why you might want to use an inverse ETF vs short selling is that there is a limit to the downside, unlike shorting. Also, even though the fees are high, they might be less than margin interest rates and the fees for borrowing shares.
You are correct about all the above. Shorting or paying someone to short on your behalf can be expensive.
The issue with these daily leveraged funds is that you probably aren't making a one-day prediction or trying to hedge a one-day bullish bet. You are probably making a 6-12 months prediction, but understand you cannot predict daily moves. Thus your timeline (6-12 mos) is out of alignment with TSLS's timeline (one day). You need a vehicle that cheaply delivers the desired outcome on the timeframe your prediction is valid.
If I was going to short the stock of a company whose CEO was lighting the brand's equity on fire, I would choose options, as others suggested. Option pricing is, in part, based on the much lower risk-free rate of return, not TSLA's short interest rate. Instead of paying some douche on Wall Street to make daily swaps and futures trades on your behalf, you just pay a buck or two commission to trade the options. The time decay of a 9 month put option, for example, might be less than the typically daily contango losses
@Financial.Velociraptor mentioned.
But your wariness is warranted. NEVER trade options without a THOROUGH understanding of what the contracts mean and the entire range of potential consequences. One must do their homework or else not throw money at it. As others have noted, when you BUY an option, the most you can lose is 100% of what you paid, whereas if you SELL an option the losses can expand to much bigger numbers than the amount you received. So you could just buy a put option, as others have suggested and only risk the amount you spent. But I'm suggesting doing the homework first. Maybe buy the put in a paper trading account, or on a post-it note.
So your cost of shorting is either to pay the Wall Street douche and endure the costs of having your timeframe misaligned with your financial instrument, OR put in several hours worth of reading to fully understand options and then get the lower cost. I think the latter is the Mustachian way, because it builds up a skill that you might need later and locks in a lower cost of doing things.
Let me know if you're interested in the educational path, because there are some links I could share.