Using Placement of Channel Type Email Content Type JSON in Journey Email Action content builder

[dmoorethree]

I have built a Placement of Channel Type Email and Content Type JSON. I have added the placement to a couple of offers and populated them with some JSON. I then go into a Journey and add an Email Action and edit the content and edit the email body. I then try to add an Offer Decision and it asks we to pick a Placement but the Email JSON placement I configured is not available in the drop down list. Why is this?

The use case is that I want to create the offers as JSON that can then be rendered across the email because we refer to different parts of the offers across many different parts of the email.