What do you think of an ActivityPub-enabled Craigslist alternative that has the following data structure?

* Listings are Create activities with a custom object type, e.g., Listing.

* Email is stored as a required field in the listing metadata (hidden from ActivityPub federation unless specified).

* Comments and replies can still use ActivityPub for public discussions but not for transactions.

The listing would be public. But communication between buyer and seller would be via email.