Why is it useful, who would benefit from it, how should it work?
As noted, features can currently be linked to a single initiative. The reason for this is that initiatives are built to represent the large strategic efforts/projects a team is working on where a feature is the individual task being worked on.
Tracking a single feature against multiple initiatives would be a duplication of work and cause down stream issues as we move to add the ability to plan capacity against an initiative.
Based on the above points and current priorities, we are unlikely to make updates in this area. We hope you can understand.