Soundwave

Is there any particular reason that Paint.net doesn't have a batch file format conversation function, either natively or through a plugin? I've seen a few requests for it, but there just doesn't seem to be anything out there. I have Irfanview for it, but I'd really prefer to have one program that does it all - and since Paint.net does everything but that, I'm really curious why it seems so difficult to take that one final step.