Like everything related to program builder, primary entity types must match. Only data card rules show up on the step actions, and further only update rules with the data card object show up.
That said.... that is one scenario I didn't think of but definitely see very useful: the ability to create a data card via program builder.
Naturally if they can't create a data card, I'm guessing they haven't built the systemic "mapping" function. Which is probably why it is throwing the error when trying to perform an update to the Data Card field flagged with the "Email Address" mapped field.
Seems like the mapped contact is dependent on enabling most of the new functionality they built in this release.
Hopefully we'll get some official Eloqua commentary here ^_^
