If you look at the crowdsourced spreadsheet* of Dataverse installations you'll find that a few of them use the "authority" 10.5072 which is only supposed to be used for testing. (I assume they're using the FAKE DOI provider as well.) These installations seem to work fine (more on this below) but in a perfect world, all installations would get their own DOI authority or use Handles. As Danny said, data citation is very important to this community.
Here are the features I believe you lose if you don't configure Dataverse to use proper persistent identifiers (DOIs or Handles):
- The ability for the data to be cited.
- The ability to click the URL form of the persistent identifier (PID) in the citation of the dataset have it "resolve" back to the dataset. This is important when you share the citation to the dataset, of course.
Using DOIs instead of Handles gives other features:
- When a dataset is published, metadata is sent to DataCite's search index.
- Citations to datasets can be retrieved via Make Data Count.
Since you mentioned migration, there are APIs in Dataverse to migrate from Handles to DOIs but I'm not aware of any tools to migrate from fake DOIs to real DOIs.
I can't think of any risks (you mentioned data loss), apart from the features you miss out on above and that you might hear again and again that you should be using real persistent identifiers for your data. :)
I hope this helps,
Phil