Why is short-term health insurance less expensive than ACA plans?

Short-term medical plans are for the “right now.”  They do not cover conditions that you might have been diagnosed with previously or been advised by a doctor to seek further treatment. The plans also don’t cover long-term medical needs, like a routine pregnancy. Short-term insurance is for protecting you going forward with any new conditions that might arise. This helps keep the cost lower than ACA plans (if you do not qualify for a financial subsidy).