Thanks Jeff, that clarifies things a bit. I think ACID transactions will be used where high-cost interactions are concerned. For example, if I'm transferring $millions I'd be happier if traditional ACID semantics were involved than transactions with compensation (if a failure occurs, I'd rather have my money back in my account now than have to wait for some lawyers to settle the dispute and get it returned from wherever it ended up - and compensations aren't guaranteed to complete anyway, so compensations may need compensations ad infinitum.)
Also, the kind of ACID transaction models in WS-T and WS-CAF seem perfect for interoperability between traditional TP systems. Something even the OMG failed to be able to pull off!
I think I understand where you are with regard to WS-CAF versus WS-T and I agree.