The limit is the reason a trader can lose heavily and still owe tax. If capital losses are trapped while wage income is taxed in full, the cash cost is immediate and the relief is spread over future years through capital-loss-carryover.
section-1256 contracts have their own escape hatch: a net Section 1256 loss may be carried back three years against prior Section 1256 gains via an election on an amended return, which can produce a refund rather than a carryforward.
Traders who qualify for trader-tax-status and make the section-475-election step outside the capital regime altogether, so the $3,000 cap does not apply to their trading losses.
This is general information for the United States, not tax advice. Rules change and depend on your circumstances; consult a professional before relying on it.
Related: capital-loss-carryover, section-1256, section-475-election, trader-tax-status, form-6781