Why is having it be syntax necessary or beneficial?

One might say "Rust's existing feature set makes this possible already, why dedicate syntax where none is needed?"

(…and I think that's a reasonably pragmatic stance, too. Joins/selects are somewhat infrequent, the impediments that writing out a join puts on the program relatively light… what problem would be solved?

vs. `?`, which sugars a common thing that non-dedicated syntax can represent (a try! macro is sufficient to replace ?) but for which the burden on the coder is much higher, in terms of code readability & writability.)