The one “risk” might be that if you need to cancel, you’ll have a VS ecredit and the ecredit will be subject to the VS fare rules, not a DL ecredit subject to DL rules. You would also have to work through VS for any advance schedule changes if you get hit with any that occur and for which you want to rebook based on the updated itinerary. If you care about MQDs, you’ll need to run the math to determine which booking method is better relative to the cost you’re paying.