Only at 12v. Even microblade molex (really small) are 250v/2.5amp, and so have no trouble with 500w. The wire insulation is rated much lower than the connector

Only at 12v. Even microblade molex (really small) are 250v/2.5amp, and so have no trouble with 500w. The wire insulation is rated much lower than the connector (105C vs 170C). You will certainly melt the wires before the connector. At a higher voltage, these wires would be fine for purpose.