We utilize milestones for a lot of our projects in a very traditional way, solely for marking a date on a timeline. For example, "To client for reveiw". Nothing else needs to happen there except to mark the status of that review in the workflow. Because there is the opportunity to use it like a regular task, it opens up a place for conversations to fork.
It would be amazing if there was the ability to turn off comments and file uploads on milestones to keep the conversations in the tasks where the work is happening. We've tried putting directions in the description fields of our milestones, but when people are in a hurry of just don't read them, conversations fork and discussions get fragmented.