Hi,
The add-ons marketplace is currently focused on application infrastructure services such as database, caching, queuing, performance management etc. I think what all these technologies/products have in common is that they're developer-facing and consuming them as-a-service through this marketplace removes a significant technical configuration and operational/maintenance concern from the developer building the app.
A CRM system wouldn't really fit that bill, and as such I think it's not appropriate for the Add-ons program at this time.
Best,
Morten Bagai
Heroku