Because you wouldn't use a screwdriver on a nail...

I spoke at the CMG 2006 conference in Reno last week (I gave a presentation on SOA and appeared on a SOA panel).   While at the conference I was confronted by a BPM-type who had lots of questions about BPEL.   After some discussion I finally got the guy to realize that BPEL is an orchestration language, nothing more.  

Trying to use an orchestration language for all of your BPM needs is like trying to drive a nail with a screwdriver - use the right tool for the right job and you'll find life is much easier.