No, FSA and HSA are similar but different. They both exist, the use-it-or-lose it variety you're talking about is called an FSA. HSAs, on the other hand, can carry over year to year, and doubles as a source of income in retirement.
The downside is you must have high deductible plan to contribute to an HSA -- the idea is that you put aside enough money to cover the high deductible just in case, but are now motivated to price comparison shop for MRIs and whatnot, since any unspent money is now yours to keep.
The downside is you must have high deductible plan to contribute to an HSA -- the idea is that you put aside enough money to cover the high deductible just in case, but are now motivated to price comparison shop for MRIs and whatnot, since any unspent money is now yours to keep.