HSAs can be useful because they're funded with pre-tax dollars, and, if you spend the money on medical expenses, you never pay taxes on them, even if you spend that money many years after you put it in. If you spend the money on non-medical expenses, you do pay taxes on it when you withdraw it, so the HSA functions sort of like an IRA with extra benefits for medical expenses.
But be sure it's an HSA and not an FSA, because in an FSA, you lose any unspent money in that account at the end of the year.
Seems like if it costs you an extra $80 but your employer puts in $500, you net $420. But my guess is there are other factors, because most HSA-eligible health plans have high deductibles too.