In the context of the trade to Washington with Harper signed, I can agree.Well there's a couple of reasons. One I like Schwarber as a player better long term. IMO Schwarber has shown he's a better hitter thus far in all metrics. One could argue Happ is a better defender but the metrics like Schwarber a lot more this year than Happ. And even if you assume the metrics are wrong on Happ, I don't think there's enough difference defensively between the two to matter. Plus, I think Schwarber's upside with his bat is far more than Happ. Happ probably has max upside of like 30 HRs Schwarber if he reaches his peak potential could probably hit 40-50.
But setting that aside, why would Washington need Schwarber? The presumption on my part is they are only going to trade Eaton if they re-sign Harper. If they do that they have Soto in the other corner and likely Robbles in CF. Happ can play 2B. Schwarber can't. After dealing Murphy the Nats don't have an obvious starting 2B.