Keep in mind that even when the underlying hardware implements TSO, what programming languages expose is basically the release/acquire model of memory semantics.
This means that as a programmer, you still have to code against the release/acquire model because the compiler may reorder your memory accesses. Having TSO in hardware is still helpful though, because it means the compiler has to emit fewer explicit barrier instructions at the end. That is, the barriers that you do have in your original code end up being a little bit cheaper (at the cost of having an overall more complex hardware architecture).
This means that as a programmer, you still have to code against the release/acquire model because the compiler may reorder your memory accesses. Having TSO in hardware is still helpful though, because it means the compiler has to emit fewer explicit barrier instructions at the end. That is, the barriers that you do have in your original code end up being a little bit cheaper (at the cost of having an overall more complex hardware architecture).