MapThread and parallel computing

May be because its easy to implement?

MapThread[f, {{a1, a2, a3}, {b1, b2, b3}}]

(* {f(a1,b1),f(a2,b2),f(a3,b3)} *)

ParallelMap[f @@ # &, {{a1, a2, a3}, {b1, b2, b3}} // Transpose]

(* {f(a1,b1),f(a2,b2),f(a3,b3)} *)

Many functional operations including MapThread can be easily parallelized by composing the function with ParallelSubmit, then collecting all concurrent jobs:

WaitAll[MapThread[ParallelSubmit @* f, {{a1, a2, a3}, {b1, b2, b3}}]]