I once said something along the lines of "all we can do is elect more and better Democrats." That isn't quite true, of course, as there are plenty of other things one can do. One can decide there are other things you can spend your time doing. One can focus on state and local politics. One can try to put pressure on the existing Democrats. One can decide that enhancing the stature of third parties is important. Lots of options.
Still to the extent that Congress has a rather important role, electing more and better Democrats is an important thing to do, if not the only thing. By accounts Darcy Burner is indeed a better Democrat, so consider unloading a few extra pennies.