In the past, the new D/E security checkpoint had a priority line which could be accessed via either a first class or premier access or equivalent ticket on any airline. I forget what the sign says but it was something not particularly obvious. I believe the entry to the line was between the CLEAR and regular security line. I would be very surprised if it was gone, particularly as the BWI website has a security wait times display and it does have a time for D/E priority.

There are times when the UA check-in counter lines are are very long and the premier access line is much shorter, it can make a considerable difference.

Whether or not its actually worth buying premier access though is questionable at best. Arriving very early is probably still the way to go. Or sign up for a CLEAR trial. I've yet to see the CLEAR line busy at D/E.