Cheaper? Definitely. Much easier? It depends on where you're coming from. I live in Adams Morgan, and I wouldn't call metro the easiest way for me to get to DCA. It would take about twice as long as taking an Uber (my usual way of getting there) or driving. I usually only take the metro to DCA when I have time to kill, don't have a lot of luggage to schlep to the metro station on foot, and the yellow line is running to Columbia Heights so I don't have to transfer.