HSAs are triple tax advantaged retirement accounts. Not taxed on contribution, gains, or withdrawals for qualified expenses. In the worst case it becomes like a pretax IRA because after age 65 you will not pay a penalty on non qualified expenses - but qualified expenses tend to increase with age. For many it should be their primary retirement account. Even for people with certain chronic conditions (not in perfect health), depending on how good/expensive the PPO offered by the employer, it might still work out better to do HDHP/HSA. You can get as many basically free HSA accounts from Fidelity.

An FSA really has nothing to do with an HSA.