Currently Idea comments & attachments don't carry over to Features. If possible, we'd like to configure features so these components carry over.
At this time, we include a link to the promoted idea so that you can see additional details with just one click. We suggest that any specific comments and attachments which are relevant, should be added to the feature description or requirements. This allows you to wade through the noise of all comments, and keep only the most important information for implementing the feature.
Based on the suggested workflow, and current priorities, we are unlikely to make updates in this specific area. We hope you can understand.
We are requesting this functionality for our dev teams in Jira. Lots of comments/questions/etc are happening on the original Ideas that provide key context. As the Idea is promoted to a Master Feature or Feature, those comments are lost. When the Master Feature or Feature lands in Jira, the original comments from the Idea are not carried over and dev teams need to go find the original Idea on the Ideas portal for the context they are looking for.