This is pretty interesting, and in a way, shortsighted. What happens if you deploy InfoPath, then all your information will be in XML format and probably stored on a server, at the very least accessible by SOAP. What the users of InfoPath are going to want is a way to share that information, with outside customers, with co-workers, etc. And that sharing may even include letting the customers query, enter or modify that information. What would be the easiest way to do that? Well via web browser, of course. And if you want to have the least friction between your InfoPath interface and the customer interface then your path of least resistance is a nice RESTian interface and XForms. If InfoPath is wildly successful, that very success may actually force Microsoft into supporting XForms.
This, of course, assumes InfoPath supports the ability to do generic HTTP PUT's and GET's and it is not just restricted to SOAP for retrieving data. I'm anxiously awaiting the beta release to get the answer to these and other questions. The above isn't such a far fetched scenario once you realize how much of Microsoft's actions are driven not by the home consumer but by their large corporate customers.
For those unfamiliar with it, XForms is the recommendation from the W3C that updates how forms work in web browsers. As opposed to the current form designs the new XForms can use XML files to populate a form with data and also use XML when posting data back to the server. It also supports the HTTP verb PUT in addition to the traditional POST and GET. Just noticed that the verb DELETE is conspicuously absent. Hrmm.