Currently existing advantage, that's still a little hard to find because EA seems to be rehashing over the same routes that Tesla already did, but there are several long commonly used routes near me that do not have Supercharger coverage, so if Electrify America would get on the ball(!) and cover these routes first, it would possibly make sense to get an adapter:
(1) Boise to Coeur d'Alene, ID. 362 miles
(2) Boise to Bend, OR. 309 miles
(3) Boise to Winnemucca, NV. 252 miles
(4) Twin Falls, ID to Las Vegas, NV. 485 miles