After looking into that, and making exactly four trades, where I sold SPX ODTE put credit spreads, I came to the conclusion that credit spreads are a siren's song for noobs. lol
From what I could determine, the risk:reward is always upside-down, so even if you sold a 10 or 5 delta spread, with a 90 or 95% chance for success, the 5-10% of the time you lost would put you in the hole once you factored in trading costs.
Another thing I didn't understand: It seems the premise for selling a (short) credit spread is because you *believe* price will close higher than your short strike at the end of the session. Yet, traders I was watching were stopping themselves out long before their short strike was even close to being threatened. And a lot of those trades would have been successful had they held all the way to the end.
Probably missing something here, but if you aren't willing to hold through the entire session, then why enter the trade in the first place? I mean, if you stop yourself out, you apparently never believed your original premise in the first place. Just didn't make sense to me.
I'm not saying you can't make money selling credit spreads, but it reminded me of how the vig (along with odds) in casinos makes it impossible to win long term. Granted, market odds aren't set in stone like in casinos, but still...