The every 20 minute thing is annoying. We have had opportunities to take the train to places over the weekend but 20 minutes is silly. An example, we went to see a movie at alamo draft house. If we time it, it's honestly about the same door to door. But if we mess up timing it isn't.
In the end we have driven over the weekend. Same with Science center and other locations near stations. The time math makes driving make more sense even though I hate driving. What makes your standard German city's subway usable is the time between trains is very short.
Once the Fairfax station opens, we plan to take the D line there. But if we do 20 minutes on weekends, we may not after the novelty visit.