To qualify for this unemployment benefit, you must be receiving federal/state unemployment insurance or paying for COBRA or other medical continuation coverage. If so, your health insurance premiums while unemployed are considered qualified medical expenses.
In essence, you could contribute to your HSA for six months, lose your job, and use those contributions to pay for your health insurance for the next six months, all tax-free. It is great peace of mind to know if you have a bad stretch, your health insurance payments are covered by your tax-free HSA contributions.
A good strategy is to build your HSA so that the account could cover six months of health insurance after a job loss. When you continue coverage that limits your total financial responsibility.
It's always nice to know you have a plan and have cash reserves to get through the worst of it. Once your situation improves, you can rebuild your HSA balance.