The 60/40 split applies regardless of holding period, so a futures day trader pays a blended rate lower than the ordinary rate that applies to stock day trading. Open positions are mark-to-market on December 31, and the wash-sale-rule does not apply.
SPX options qualify; SPY options do not, because SPY is an ETF, not an index. This is a common reason index-option traders prefer SPX.
Example: a trader with $50,000 of futures gains in the 32% ordinary bracket pays roughly 32% on $20,000 and 15% on $30,000, about $10,900, versus $16,000 if it were all ordinary income.
Related: mark-to-market, wash-sale-rule, futures-contract, cftc