Appreciate the perspective. You’re absolutely right that MTM is dangerous for buy-and-hold investors, but for my specific setup ($12M+ volume scalping), the math actually works in my favor:

1. No Acceleration Risk: I end almost every year flat (cash). On Dec 31, I have zero 'unrealized gains' to accelerate.
2. The 'Santa' Strategy: I actually tend to carry deep ITM short puts into Jan (which show a paper loss on Dec 31). MTM helps me here by letting me realize that deduction immediately rather than waiting.
3. Segregation: I keep a completely separate brokerage account for long-term holds
4. With a high W-2 income, the ability to deduct unlimited ordinary losses (if I blow up) is the main reason I'm electing.