Windows Workflow Foundation and BizTalk 2006

I have been playing with Windows Workflow Foundation for the last hour, just following the lab. To early to judge it, just on a one hour experience, but to me, as a BizTalk developer, I see a lot of similarities between WWF and BizTalk orchestration. Which makes me wonder...

If BizTalk is beta1 and WWF is beta1, is Microsoft going to publish two technologies in roughly the same timeframe (estimated on release numbering, but I haven't seen an announcement on WWF's availability yet), delivering roughly the same functionality, but completely uninterchangeable? I don't understand. I see a lot of additional value in BTS2006 over WWF, so I can account for the licensing costs. But I wouldn't want to invest in building BTS orchestrations when the technology that going to replace it is already available, or would I?

NOTE: These are thoughts from the head, based on assumptions and incomplete information. I'm just wondering and hoping some of you do have more information on this.

UPDATE: Ilske pointed me to some information in the WWF article from David Chappell. It features a decision list on when to choose which technology. Although I think this list is very sensible, I still think that investing in XLANG orchestrations is a tough decision when you not only know the technology is going to be replaced but also have the replacing technology available. Or am I missing a point here?